Chapter 19 HERBACEOUS ORNAMENTALS

IDAHO MASTER GARDENER UNIVERSITY OF IDAHO EXTENSION

I. Introduction 2 VI. Getting Started with Annuals 5 II. The Art of Design 2 A. Propagation 5 A. Color 2 B. Growing, Culture, and B. Texture 3 Maintenance 6 C. Shape and Size 3 C. Description of Selected Annuals 9 III. What to Plant 3 VII. Getting Started with Biennials 10 A. Exposure 3 VIII. Getting Started with Perennials 10 B. Season of Flowering 3 A. The Purpose of a C. Cut and Dried Flowers 3 Perennial Garden 11 D. Herbaceous Ornamentals B. Sexual Propagation by Seed 11 That Naturalize 4 C. Vegetative Propagation by E. Special-Use Gardens 4 Division, Stem Cuttings, Root Cuttings, Layering, Grafting, or IV. How to Plant (Design) 4 Tissue Culture 12 A. Formal and Informal 4 D. Vegetative Propagation by B. Beds and Borders 4 Specialized Stems and Roots 13 C. Plant Choice 4 E. Growing, Culture, and V. Gardening in Containers 4 Maintenance 14 A. Containers 5 IX. A Selection of Perennials for Idaho 17 B. Soil 5 Further Reading 28 C. Planting 5 D. Watering 5 E. Maintenance 5

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 1 Chapter 19 Herbaceous Ornamentals

JoAnn Robbins, Extension Educator, Jerome County, Jerome M. Michael Colt, Extension Horticulturist Emeritus, Parma Research and Extension Center

I. Introduction white. A darker version of a hue is a shade, a color made by combining a hue with Herbaceous ornamentals comprise the nonwoody black. A tone is made by combining various portion of the garden landscape. These plants amounts of black and white, or gray, with a generally add color and interest to a basic land- hue. The value of any color is the brightness scape design and landscape structure. Whether of that color compared to another. Pure yel- that structure is a backdrop or basic design of low has a greater value than pure blue. trees and shrubs, or a purposeful laying out of beds and other types of planting areas, the addi- The warm colors of yellow, red, and orange tion of herbaceous ornamentals can enhance a will brighten cool, shady areas. These colors landscape significantly. These plants are also for- are attention getting and can be used to the giving because they are easier to dig and re- advantage at the back of a long bed to arrange than most landscape trees and shrubs. shorten the perspective. The cool colors of Learning to use herbaceous ornamentals to the violet and blue, by contrast, recede and are best advantage is easy; simply follow the guide- good for close-up viewing. Cool colors are lines outlined in this chapter. used to the advantage in lending a cooling illusion to any overheated area such as a II. The Art of Design concrete patio. A.Color Fig. 1. The color wheel. Herbaceous ornamentals are generally grown for their addition of color, through their flowers and foliage, to the landscape. Red orangeRed Red Understanding the impact of colors and how violet to combine them can form a basis for use of Orange

these versatile landscape plants (Fig. 1). 6 Several color schemes can be created in a Violet

single garden by planting early season Yellow

green blooming plants in one color scheme and

late-blooming plants in a different scheme. Blue Triadic harmony

violet

An interesting overlap can occur in plans of Yellow

this type. Direct complement

The primary colors are red, yellow, and Blue 6

blue. Other colors are combinations of these orange Yellow

primary colors. A pure color is a hue. A green

Blue lighter version of a hue is a tint, which is Green accomplished by combining a hue with

19 - 2 HERBACEOUS ORNAMENTALS CHAPTER 19 Color schemes effectively used with herba- vision. Plants with tiny leaves and small ceous ornamentals are: flowers lend a fine texture to the landscape, 1. Polychromatic—Uses all the colors and and tend to recede in your field of vision. their tints, shades, and tones. This can Choose herbaceous ornamentals according produce a carnival effect, and often re- to the textural “feel” you wish to attain. Of- sults in some very pleasing color combi- ten a mix of all textures is most visually nations. pleasing. 2. Monochromatic—Uses the various tints, C. Shape and Size shades, and hues of only one color. Gar- Herbaceous ornamentals come in all sizes dens using this color scheme are particu- and shapes. Size is comprised of height, or larly dramatic. tallness, and spread, or the extent to which 3. Analogous—Uses adjacent colors on the the herbaceous ornamental covers the color wheel such as blue, violet, and red. ground at maturity. A shape is the same as Such a color scheme can be expanded by the habit or form of a plant. Some herba- using the various tints and shades of each ceous ornamentals hug the ground, while of the colors. others tower to 6 feet or more; others are 4. Complementary—Uses opposite colors on vines. Some are compact ball-shaped plants the color wheel such as red and green, while others are open and upright. There are orange and blue, and yellow and violet. herbaceous ornamentals perfect for any lo- This type of color scheme is most effec- cation. Be sure to space plants far enough tively used with pure hues (not tints or apart to allow room for each to develop to shades) and creates a very bold effect. maturity. This color scheme is not recommended for the small garden. III. What to Plant 5. Split Complementary—Uses a pure color A.Exposure and a color from either side of its Herbaceous ornamentals can be adapted to complementary counterpart. An example all types of sites from full sun to pure shade. of this is starting with blue and combin- Choosing a plant according to the exposure ing it with red or yellow, the colors bor- of the site ensures success with these plants. dering orange on the color wheel. B. Season of Flowering 6. Triadic—Uses three colors that are equal Some herbaceous ornamentals are tolerant distance from each other on the color of cool temperatures and bloom in early wheel. This unusual idea is striking. spring. Others need warmer weather and 7. White—This color deserves a special bloom in the summer. Still others bloom in comment. There have been many famous the fall. Choose the proper herbaceous orna- gardens planted in white flowers alone. mental based on when color in a particular There is a special appeal in the contrast area is most desirable. of white against the green foliage of C. Cut and Dried Flowers plants. White will give your garden a Some kinds of herbaceous ornamentals hold well-planned and orderly look. It is the up better as cut flowers while others dry last color to fade from sight as darkness beautifully. Choose herbaceous ornamentals falls, so it is a good choice for “evening” that are adapted to fresh or dry display. gardens. Cream and ivory flowers blend Special cutting gardens can be completely well with all colors except yellow. harvested for flowers without concern for B. Texture how the garden looks. However, plants This is dictated by the density and size of valuable for cut flowers can usually be in- individual leaves and flowers. Plants with corporated into the main garden. large leaves and large bold flowers have a When cutting for air drying, choose flowers coarse texture, tend to be dominant in a gar- just reaching maturity. Strip off the foliage, den, and appear to advance to your field of and hang upside down in small bunches in a

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 3 dry, shady spot. Some flowers will dry well Herbaceous ornamentals can also be tucked standing upright in a container. here and there in a shrub or perennial bed or D.Herbaceous Ornamentals That Naturalize border to provide a spot of seasonal color. Some herbaceous ornamentals, such as na- Avoid spots, however, where water-greedy tive plants or wildflowers, reseed them- roots of trees and shrubs will interfere with selves prolifically and eventually will natu- growth. In these spots, a container of herba- ralize an area. Know which plants have this ceous ornamentals will provide better re- tendency, and choose the proper annuals for sults. naturalizing. Remember, any hybrid orna- C. Plant Choice mentals that reseed will not come true-to- Materials will depend on the desired effect type, and usually will produce an offspring and will be influenced by color scheme, sea- of inferior plant quality. Seedlings of this son of flowering, texture, diversity, type of type are not desirable. background plants, and available space. E. Special-Use Gardens When designing the bed or border, remem- Herbaceous ornamentals are used to create ber to place the lower growing plants to the gardens with special qualities such as rock front so that they will be visible and not gardens, bog gardens, prairie and meadow shaded out by taller types. gardens, cottage gardens, cutting gardens, Since it is easier to place the tallest plants fragrance gardens, herb gardens, or tradi- first, design the border from the back to the tional herbaceous perennial gardens. front; the bed from the middle to the edge. Design from fall to spring rather than spring IV. How to Plant (Design) to fall. This ties in with the suggestion to A.Formal and Informal design from the back to the front of the bor- der and from the middle to the edge of the Once you have decided where to plant her- bed, since fall plants are often taller and baceous ornamentals, decide on a design. would logically be placed in the back of the Formal designs are composed mostly of border or the middle of the bed. Finally, be- straight lines and symmetry. What appears cause you read from left to right, design on the right side of the garden is matched on from left to right. the left. A formal design is easy to lay out and, because of its visual simplicity, is the Plant in clumps or drifts of plants using best choice for a small lot. groups of the same species or cultivar. When planting in groups of less than 10, Informal gardens are composed of curved plant odd rather than even numbers of the flowing lines and a disregard for symmetry. same plant. These design suggestions help B. Beds and Borders avoid the “zoo” effect (a collection of one Beds are large blocks of planted areas. The of everything) and will lead the eye through bed requires a relatively large area around it the planting. to look its best. If you have a large yard you may have the perfect spot for a bed. V. Gardening in Containers Borders run along the edges of shrub beds, Almost any annual can be grown in a con- buildings, fences, walkways, and lawns. tainer. Plants that spread or cascade are suit- They conserve space and soften the edges of able for the outer rim of regular containers and whatever they border. for hanging baskets. If plants are mixed in a As a general rule, the sum of the widths of container, all should have similar sun and wa- the beds and borders should not exceed one- ter requirements. Containers and hanging bas- third of the width of the yard. Also, indi- kets allow the gardener to provide spots of vidual beds should be no more than five- color almost anywhere around the home eighths to two-thirds as long as the long axis grounds. of the yard.

19 - 4 HERBACEOUS ORNAMENTALS CHAPTER 19 A.Containers will germinate and grow in cooler soil. The Choose a container with holes in the bottom plants will stand some freezing and thawing. to drain the water. A tray underneath will Half-hardy annuals will take some cool, damp catch any drainage. Avoid letting pots rest weather but will be killed by a frost. Tender in standing water, as roots may begin to rot. annuals can take no cool weather at all. Some Glazed clay pots and plastic containers do annuals will reseed depending on variety and not breathe and will not need watering as climatic conditions. often as clay. Darker colors absorb more Annuals serve many functions in the garden, heat, which will warm the soil but cause but their primary use is for providing color. more water loss. Therefore, light-colored They grow quickly and easily, are great for containers may be the best choice for most cutting, and are generally inexpensive. Annu- gardeners. als generally bloom for most of the season. An B. Soil added bonus is the fragrance that some annuals For containerized plants, purchase a com- bring to the garden. Annuals come in a variety mercial potting mix that is a blend of peat, of sizes, shapes, and colors. pearlite, and other components and contains A.Propagation no soil. Mixes are blended to hold water and 1. Seeds—Come in mixtures and single cul- nutrients and to drain well. Mix some slow tivars. Hybrid seeds are usually more ex- release fertilizer with the mix, or liquid feed pensive but often produce spectacular about every 2 weeks. Water containers well flowers. If you save your own seed, be before applying liquid fertilizer. aware that most flowers, and especially C. Planting hybrids, will not breed true-to-type. Containers look best when packed with Seeds will lose their viability if stored for plants. A planted container should look at- many years, so starting with fresh seed tractive immediately after or within a few packaged for the growing year will get weeks of planting. you off to the best start. D.Watering Seeds that are started indoors or in a greenhouse should be growing 4 to 6 Plants in containers require regular water- weeks before you place them in the gar- ing. Always water until the water runs out den. The warm weather annuals should of the drain holes. Water can run right be transplanted outdoors after the danger through very dry soil without actually wet- of frost. ting it. If you have doubts, tip the container up to test that it has become much heavier The easiest way to begin annual plants is with water. to plant the seeds directly where you wish the plants to grow. The seedlings E. Maintenance can be thinned to achieve the desired Herbaceous annuals make excellent long- density. Follow the seed package instruc- flowering container plants. However, peren- tions for time and depth of planting. nial container plants can be placed in the 2. Transplants—Plants from the garden cen- garden after their limelight. If containerized ter save you time and effort. They are, perennials are not planted out in the garden, however, more expensive than growing place them in a cold frame or garage to pro- your own. Some flowers such as petu- tect their roots from freezing during the nias, impatiens, and geraniums have very winter. small seeds, are slow to germinate, and VI. Getting Started with Annuals seedlings take longer to reach transplant size. They can be started indoors, but An annual plant completes its life cycle in a they demand precise growing conditions single year. Unless the plants reseed them- and vigilant care. It is easier to buy trans- selves, new annuals need to be planted every plants for these types of plants. season. Some hardy annuals have seeds that

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 5 Pick good plants. Make sure plants are even with the surrounding soil surface. healthy and growing vigorously. Plants Recent research has shown that breaking that have obviously dried out, have over- up the root ball of even the most pot- grown their containers, or are yellow or bound of annuals only slows down their leggy should be avoided because they development. Plant the roots as they will bloom poorly and require constant come out of the container. Do not let the watering. root ball dry out. Firm the soil around the Slip plants out of their containers to roots and water well. Protect plants check the roots. Look for a fine network against excessive sun, wind, or cold of healthy roots supported by visible soil. while they are getting started. Inverted Avoid plants with a mass of dense, white, pots or milk cartons, or row covers can tangled roots. be used. B. Growing, Culture, and Maintenance 3. Fertilizing—Dry or liquid fertilizers will 1. Soil preparation—A soil test is always a work for annuals. Nitrogen stimulates good idea if there is any doubt about the leafy growth, while phosphorus and pot- fertility or pH of the soil. Amend the soil ash promotes flowering, fruiting, and root appropriately before planting to adjust growth. Fertilizers with a ratio of 1-1-1, the acidity and provide the proper nutri- 1-2-1, or 1-2-2 are best for annuals. Re- ents for growth. member that the numbers on the package indicate both the ratio and the percentage Amendments, such as compost, peat of active ingredients per pound of nitro- moss, and manure added to the soil will gen-phosphorus-potassium. increase organic matter, and thereby in- crease water-holding capacity and soil Dry fertilizer amendments added at plant- fertility. Covering the soil surface with a ing will last for about 6 weeks. Applica- 3-inch layer of amendment and digging it tion of dry fertilizers, followed by a wa- into a 12-inch depth provides a good tering, or liquid fertilizer applied to damp planting area. soil will maintain the quality of the plants and blooms. 2. Planting—Seeds will germinate when the soil is warmed to the proper temperature. 4. Watering—Young plants need more fre- The exact temperature will depend on the quent watering until their roots get estab- annual species being planted. lished. Sown seeds may need multiple daytime watering. As plants become es- After the soil is prepared, sprinkle the tablished, gradually water less frequently. seed either randomly or in rows with in- Watering established plants will depend dentations in the soil. Cover the seed with on plant size, soil characteristics, and loose, organically amended soil, so the weather. During hot weather, large plants soil will not crust over the seeds. Water in sandy soil require frequent watering. in with a light misting of water, and keep Strive to keep the plants evenly moist. If the soil evenly moist until germination plants are allowed to dry out, they may occurs. Be sure not to plant the seed any be permanently stunted. deeper than suggested on the seed pack- age label. Overhead watering with sprinklers is a common technique. However, some Acclimate transplants before placing flowers are more susceptible to disease if them in the soil. Place them in a pro- their leaves and flowers are constantly tected space outdoors for several days, wet. Overhead watering can also cause and make sure the plant does not dry out. taller plants to tip over. At planting time, tap or tip the plants out of their pots, and set them in a prepared Furrow watering is a common technique hole large enough for the root ball to fit if planting is done in rows. Furrows must comfortably. Set the plant in the hole, be tended so the water flows properly, making sure the top of the root ball is and there must be a gentle slope from one

19 - 6 HERBACEOUS ORNAMENTALS CHAPTER 19 end to the other. Once plants get large, frost problems. After plants are well es- the furrow system can be difficult to tablished, a second thinning will leave maintain. plants with plenty of room to attain a ma- Drip irrigation is the most efficient way ture growth. Properly spaced plants are to deliver water. Use drip emitters or per- healthier and produce more blossoms. forated tubing to deliver water directly 7. Pinching—Removing the terminal where you want it. growth on young annual plants will help Infrequent deep watering is better than make them bushier and more compact. frequent light applications. Many annuals are now bred to be com- 5. Mulching—This helps annual plants con- pact and well branched. However, any serve moisture and keeps the soil cooler. plant that has become too leggy or too Be sure to apply the mulch after the soil tall will be improved by pinching. Ex- has warmed in the spring, otherwise amples are petunias, geraniums, and warming will be delayed. Mulches also many chrysanthemums. help in weed control and provide an at- Pinching out the first blossoms that form tractive appearance. Organic materials, on some plants will cause more overall such as bark or sawdust, can be incorpo- bloom. Examples are marigolds and zin- rated into the soil at the end of the season nias. as an organic amendment. 8. Weeding—These rob annual plants of Mulch materials must allow water to nutrients and water and make them look move through. Organic materials must be unkempt. Weed problems can be reduced loose and coarse. Remember that many by proper soil preparation and mulching organic materials will draw nitrogen to immediately after transplanting. In direct- the soil to aid in breakdown. These mate- seeded areas, apply mulch to retard weed rials, when used as mulch, must be aug- growth after plants have been thinned. mented with nitrogen fertilizer. Wood If weeds grow among annuals, hoe only byproducts, such as bark chips and saw- deep enough to sever the weeds just be- dust, as well as compost make good low the surface. This will avoid any dam- mulch for annuals. Pine needles and grass age to the shallow feeder roots common clippings can also be used. Spread grass to annuals. If weeds are large, pull them clippings in one thin layer and allow by hand. them to dry before adding another layer. 9. Deadheading and grooming—Removing Landscape fabric can be spread over the the faded flowers, or deadheading, will soil surface and covered with bark chips help keep the garden looking neat and or other organic materials. The fabric will prolong bloom on most garden annu- stops weed growth, but allows air and als. A plant that is ripening seeds pro- water to penetrate the soil. duces less blossoms. Pinch off or cut 6. Thinning—Seedlings grown from di- spent flowers back to the next branch. rectly planted seeds need to be thinned. Shearing the flower heads with pruning This process is little more than pulling shears works well for smaller-flowered out the excess seedlings to establish the plants. Be careful not to cut back too far. proper spacing for the type of annual Remove less than one-third of the plant. grown. Grooming annuals involves removing If pulling will disrupt the roots of the re- dead leaves and thinning extra branches. maining plants in the garden, clip off the Grooming keeps plants looking good and, extras at the soil line with shears. Leav- by removing dead foliage before it can ing more plants than necessary at this mold on the plant, keeps diseases from first thinning will provide some plants to gaining a foothold. be transplanted elsewhere and also allow Thinning the foliage keeps the air circu- a margin of safety in case of disease or lating through the plants, keeps the plants

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 7 dry, and cuts down on diseases. Thinning ticidal soaps. Caterpillars can be con- also allows light penetration to the inte- trolled with Bt spray. Earwigs can be rior of the plant. Often insect pests, trapped in rolled newspapers and then which otherwise might be overlooked, destroyed. are discovered during the grooming. If chemical treatment becomes necessary, 10. Staking—Tall growing annuals such as make sure your pest is positively identi- larkspur and tall marigolds need protec- fied and use a chemical appropriate for tion from wind and rain or overhead its control. Always follow label direc- sprinklers. Stakes help them grow tions. straight and keep them from being 12. Diseases—Since annuals are only in the knocked over. garden for one season, diseases are not as Stakes can be made of wood, bamboo, or serious a problem as they are for perenni- any similar material. To be less conspicu- als. The following diseases, however, can ous, stakes should be small in diameter sometimes cause problems: the fungus and about 6 inches shorter than the ma- diseases botrytis blight (gray mold), ture plant to avoid being visible above damping-off fungus, powdery mildew the plant. Secure the stems to the stakes and rust, and the virus diseases mosaic with paper-covered wire, plastic ribbon, and aster yellows. or other material that will not cut into the Moist conditions and splashing water fa- stem, You also can support the plants vor and spread the fungus diseases rust, with a framework of stakes and strings in powdery mildew, damping-off fungus, crisscrossing patterns. Commercial sup- and botrytis blight. Spacing and groom- port frameworks are available for herba- ing plants correctly to maintain a good ceous annuals. airflow will help to prevent these dis- Stake plants before they have a chance to eases. Sprinkler watering in the morning fall over or begin to grow crooked. When so the foliage will dry during the day or plants are about one-third of their mature drip irrigating so the foliage stays com- size, begin staking. Place stakes or pletely dry will also help. Damping-off frames close to the plant, but take care can be prevented by planting seeds after not to damage the root system. Secure the the weather warms and not keeping the plant stems to the stake or frame as it seeds and seedlings too wet. grows taller. Botrytis gains a foothold in dead plant 11. Insects—Although ornamental annuals parts. Deadheading and grooming can are generally pest-free, the following in- help to keep this disease out of annuals. sects can sometimes cause problems: Insects such as aphids and leafhoppers aphids, beetles, caterpillars, thrips, white spread the virus diseases mosaic and aster flies, earwigs, and mites. yellows. Starting with virus-free plants Annuals that are well maintained can and then excluding insect pests will de- withstand most attacks by insects. Plants tour these diseases. No control is avail- under water stress or those lacking plant able for the virus diseases. Plants must be nutrients become more susceptible to in- pulled and destroyed. The fungus dis- sect attack. Keeping annuals healthy and eases are controlled with fungicides. growing is the first line of defense. Many Check the label of each chemical for the insect pests are naturally controlled by organisms controlled and proper applica- predator insects. Chemical sprays will tion methods. destroy these predators and should be 13. Other pests—Slugs and snails are very avoided. common and can chew small annuals Insects, such as aphids, mites, thrips, and down to nothing. Handpick, trap, and de- white flies, can be controlled with insec- stroy the pests, or use commercial baits.

19 - 8 HERBACEOUS ORNAMENTALS CHAPTER 19 C. Description of Selected Annuals These seed-grown plants will form tubers 1. Antirrhinum majus (Snapdragon)— that can be dug and stored over the win- Available in many colors. Grows in full ter. To assure vigorous bloom, however, sun. Height varies from 12 inches for replant each spring from seed. These dwarf plants to 36 inches for the tall vari- showy plants will bloom profusely in the eties. Plants can be directly seeded or first year. transplanted in early spring. These plants 8. Ipomoea tricolor (Morning glory)—Col- often reseed themselves under Idaho con- ors include blue, white, pink, red, choco- ditions. late, crimson, lavender, and violet. Grows 2. Begonia semperflorens (Bedding bego- in full sun. This climbing plant will grow nia)—Colors in shades of red and pink, to 10 feet, but some dwarf forms are and white. Leaves are bright green or available that grow to 5 inches. This fast- bronze-red and waxy looking. Grows in growing vine is attractive on trellises and partial sun to shade. Height is 6 to 12 fences. Flowers on old varieties are open inches at maturity. Seeds are slow to start only at night, but the newer varieties stay and are best used as bedding plants or open most of the day. Several different houseplants. species are available. Some will reseed. 3. Calendula officinalis (Pot marigold)— 9. Lathyrus odoratus (Sweet pea)—Comes Flowers are white, cream, orange, yel- in pink, red, purple, lavender, white, low, and apricot. Grows in full sun. Ma- cream, apricot, salmon, maroon, and ture height is 12 to 30 inches. Sow seeds bicolors. Prefers full sun. Climbing types directly in early spring. Flower petals are will grow to 5 feet while bush types grow edible, and the flowers make long-lasting to 12 to 36 inches. Can be planted very cut flowers. These plants are very easy to early. Keeping seed pods off plants will grow and will reseed profusely. keep it blooming. 4. Callistephus chinensis (China aster)— 10. Limonium sinuatum (Statice)—Colors Asters come in white, light yellow, pink, include blue, lavender, white, rose, yel- red, blue, and lavender or purple. Grows low, apricot, and peach. Prefers full sun. in full sun. Height varies from 6 to 30 Grows 10 to 48 inches tall. This plant is inches. Sow seeds directly into garden in easily dried and is decorative in bou- spring. These plants dislike being trans- quets. Various forms yield plants of dif- planted. Many flower forms are available, fering heights. L. sinuatum has flowers in and they all make excellent cut flowers. flat-topped clusters while L. suworowii 5. Centaurea sp. (Bachelor’s button)—Col- has curved spikes of bright rose or lilac ors vary from blue, pink, rose, purple, flowers. yellow, and white. Grows in full sun. 11. Lobelia erinus (Lobelia)—Colors include Height is 12 to 36 inches tall. The differ- white, cream, rose, pink, purple, violet, ent species have differing planting and and lavender. Grows in full sun to light growth requirements. shade. Height is 4 to 6 inches. Lobelias 6. Cosmos sp. (Cosmos)—Colors are yel- are easy to establish as transplants. Flow- low, orange, red, white, pink, and ers best when nights are cool. Attractive bicolors. Grows in full sun to partial in front of other annuals and in containers shade. Height is 2 to 7 feet. Easy-to-grow and hanging baskets. plants make good backgrounds for other 12. Pelargonium sp. (Geranium)—Comes in annuals. Several different species have shades of red, pink, orange, violet, white, differing planting and growth require- and bicolors. Grows in full sun to partial ments. These plants will reseed. shade, depending on variety. Height is 8 7. Dahlia sp. (Dahlia)—Comes in all colors to 36 inches. These popular annuals can except blue. Requires full sun for at least be planted as rooted cuttings or as trans- half the day. Height is 12 to 20 inches. plants in spring. Several different species

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 9 have differing growth habits. All make inches. Violas are easy to establish as good houseplants. They can also be over- transplants are popular for containers, wintered in a cool, unheated cellar. hanging baskets, and rock gardens. These 13. Petunia hybrida (Garden petunia)—Col- plants grow best in early spring through ors available include shades of pink, red, early summer. Some varieties are more salmon, coral, yellow, cream, blue, heat tolerant than others. The various purple, white, and bicolors. Plants prefer species have various flower and growth full sun. Height is 8 to 27 inches. They characteristics. They will bloom all sum- are best started as transplants. The long mer in cool regions if plants are dead- blooming period of petunias make them a headed but will need to be replaced in hot popular annual. Flowers are single or summer climates. double. The plants are adapted to a wide 18. Zinnia elegans (Garden zinnia)—Comes range of soil and water conditions. They in shades of white, yellow, orange, red, also make good cut flowers. pink, purple, and bicolors. Plants grow in 14. Portulaca grandiflora (Moss rose)—Col- full sun. Height is 6 to 36 inches. Zinnias ors include white, cream, yellow, orange, are easily started from seed. These plants red, and pink. Grows in full sun. Height grow easily and bloom through the heat is 6 inches. Sow seeds directly or set out of summer and into late summer when transplants. This favorite grows in sunny, most other annuals have finished. Avail- dry areas where many other plant will not able in dwarf and tall growing varieties. grow. Plants have a trailing habit, and the leaves are succulent. Flowers are single VII. Getting Started with Biennials or double and open in the sun and close Biennial plants complete their life cycle in 2 in late afternoon. These plants look good years. During the first year plants produce in rock gardens, containers, and hanging leaves that are often close to the ground and baskets. arranged circular in nature. This rosette of 15. Tagetes sp. (Marigold)—Colors available leaves overwinters, and the winter cold period include white, off-white, yellow, orange, stimulates flowering during the second year. and orange-red. Plants grow in full sun. The plants bloom and then die. Height is 4 inches to 4 feet. They are eas- Biennial seeds can be planted in midsummer to ily established from seed or as trans- produce plants that develop in the fall. The plants. Marigolds bloom continuously plant will then bloom the next year. Popular from early summer until frost. All are biennials are stock, foxglove, silver dollar, and good as cut flowers. The many different hollyhock. species have various flower forms and Culture of biennials is the same as for annuals plant growth habits. except the plants remain for 2 years. 16. Tropaeolum majus (Nasturtium)—Colors include cream, yellow, orange, red, and VIII. Getting Started with Perennials pink. Plants grow in full sun. Height var- Historically, herbaceous perennials have al- ies from 15 inches in the dwarf varieties ways been an important component of the or- to 10 feet in the climbing types. They are namental garden, and recently there has been easily established from seed, but plants an upsurge of interest across the United States do not transplant well. Young leaves and in the culture of herbaceous perennials. De- blossoms have a peppery flavor and are spite this renaissance, many gardeners are re- edible. Blooms profusely throughout the luctant to try growing herbaceous perennials summer until frost. because they still lack appreciation and knowl- 17. Viola sp. (Pansy)—Colors available in- edge about them. clude white, yellow, orange, red, purple, Herbaceous perennials take the name herba- blue, and bicolors. Plants grow in full sun ceous from the word herb, a seed-producing or partial shade. Height of plants is 8 annual, biennial, or perennial that does not

19 - 10 HERBACEOUS ORNAMENTALS CHAPTER 19 produce woody stems. Herbaceous perennials A.The Purpose of a Perennial Garden are termed perennial in that they take one or A perennial garden may have different pur- more seasons to go from seed to seed, and then poses and fill many needs. The great En- generally, but not necessarily, live for three or glish gardener, Gertrude Jekyll (1848- more seasons. Some, such as columbine, may 1933), perhaps said it best when she be short-lived, while others such as peony will penned: outlast several generations of the same family “The first purpose of a garden is to give in the same site without being divided or happiness and repose of mind, which is moved. more often enjoyed in the contemplation The tops of the plants, the flowers, the leaves, of the homely border…than in any of and the stems of herbaceous perennials usually those great gardens where the flowers die back to the ground with the first fall frost. lose their identity, and with it their hold The hard, fleshy subterranean portions of the of the human heart, and have to take a plant, the crown and roots, survive the winter lower rank as mere masses of color fill- and resume growth in spring. Those herba- ing so many square yards of space.” ceous perennials that survive the winter with Among the uses of a perennial garden might little or no protection are termed hardy. Those be to: herbaceous perennials that need some protec- • Enhance those outdoor areas where you tion to survive the winter outdoors are said to will spend much of your time from spring be half-hardy. Some herbaceous perennials to fall. must be lifted as tubers, rhizomes, or bulbs, stored overwinter or placed in a greenhouse, • Create an attractive privacy screen. and then be replanted in spring. These plants • Soften and make attractive a steep slope are termed tender herbaceous perennials. by terracing it and planting herbaceous Herbaceous perennials are available in an un- perennials. limited variety of flowers, foliage colors, tex- • Create a bog garden where it is too wet tures, forms, spreads, and height. As a group, for a lawn. herbaceous perennials are the first plants to • Create an inviting entrance to your house. bloom in the spring and the last to fail with the • Grow flowers for indoor or outdoor fra- fall frosts. They seldom bloom more than a grance. few days to several weeks as individuals, but • Integrate the other features of the land- afford a continuity of bloom as a bed or bor- scape into a whole. der. • Create a special place to exhibit your Being herbaceous rather than woody, herba- skill at raising specimen plants. ceous perennials have the capacity to bend in • Mask unattractive aspects of the yard the breeze and lend interest and movement to a such as tool sheds, garbage cans, compost static landscape. They have the advantage, un- bins, etc. like trees and shrubs, of obtaining a definite • Use a rocky outcropping as a rock garden size each season, somewhere between a few rather than trying to remove the rocks. inches to 10 feet tall. Generally, herbaceous perennials need division and no pruning. • Create a stunning view from inside the house. Herbaceous perennials vary in their environ- mental preferences from wet to dry, fertile to • Add color, shape, and dimension to the infertile, low to high pH, sandy to loam to clay small yard patches next to entrances, soils, as well as shady to sunny sites. They also which will soften the hard features of the vary widely in the amount of care they need. existing backdrop. While there are no maintenance-free herba- B. Sexual Propagation by Seed ceous perennials, there are many that require This method is advantageous because dis- low maintenance. ease is not as easily carried over on the seed as it may be through vegetative propagation.

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 11 To start herbaceous perennials from seed, habit when they are dug and divided. For harvest the seed when it is ripe but before example, compact shallow-rooted plants the spent flower heads self-sow. Keep in are divided by digging the entire clump mind that seeds of many horticultural culti- and pulling it carefully apart into smaller vars will not come true-to-type owing to its plants. Solid clumps of plants such as hybrid parentage. To start perennials from daylilies, hosta, phlox, and Siberian iris seed indoors, start them in midwinter to are divided by digging up the entire early spring so some of them will bloom the clump and using two spading forks back- first growing season. Seeds may be started to-back to pull the clump into sections. If in a greenhouse or a sunny window but the center of the clump is deteriorated, it most commonly are started under lights. must be discarded. If you wish to have a C. Vegetative Propagation by Division, Stem small section of an existing clump for use Cuttings, Root Cuttings, Layering, Grafting, elsewhere, use a sharp spade to dig a or Tissue Culture healthy section away from the parent Vegetative propagation guarantees that the clump without disturbing the parent clump. offspring will be identical to the parent. Shallow-rooted ground covers such as Usually it takes far less time to have a fully vinca and creeping phlox are divided mature blooming herbaceous perennial anytime during the growing season by when it is vegetatively propagated. digging them up and cutting them apart. 1. Division—This is the simplest and most Fibrous- to woody-rooted perennials such certain way to propagate, control the size as lupine must be dug carefully, the soil of, and rejuvenate herbaceous perennials. rinsed from the roots, and then the crown Generally, perennials become larger each carefully divided with a sharp knife, year and eventually begin to choke out making sure that each segment contains other plants. Their outer edge thrives two to four strong tap root segments and while the center of the clump suffers two to four eyes or shoots. from competition for water, nutrients, 2. Tip or stem cuttings—These are rootless root run, and sunlight. Often an ad- sections of plants that are placed in a vanced-age clump looks like a doughnut rooting medium where they are induced with a thriving outer ring and a dead cen- to develop adventitious roots. Cuttings ter. Such a clump is a prime candidate for may also be taken from actively growing division. Shasta daisies, chrysanthe- roots. mums, and phlox are good examples of Tip or stem cuttings are propagated by plants where this condition exists after 2 taking a terminal, 3- to 6-inch long firm to 3 years. portion of a vigorous nonblooming shoot The time to divide a perennial clump de- that includes several nodes. Spring is the pends upon the particular perennial, the best time to take cuttings from herba- time of year that the perennial blooms, ceous perennials that bloom in summer. and the climate. In Zone 5 or colder, most Early summer is the best time to take cut- division is done in the spring while the tings from those that bloom in spring or perennials are still slightly dormant. Divi- fall. sion is usually necessary only every 2 to Most perennials cuttings should begin to 4 years for most perennials. Some peren- develop roots in 1 to 2 weeks. Bottom nials such as the chrysanthemum benefit heat will speed the rooting process but is from being divided every year while oth- not necessary. ers, such as the oriental poppy, are best Sometimes young, virtually rootless tufts left undisturbed for as long as possible, or of shoots develop at the base of the pe- never divided. rennials. These may be pulled away from Different types of perennials are handled the parent plant and treated the same as differently depending upon their growth any cutting.

19 - 12 HERBACEOUS ORNAMENTALS CHAPTER 19 3. Root cuttings—These cuttings are best beyond the facilities and capabilities of made in early spring. While it is easiest the ordinary homeowner. to take cuttings from perennials when D.Vegetative Propagation by Specialized they are being lifted from the bed or bor- Stems and Roots der, cuttings can also be taken from the These function primarily as food storage parent plant by digging around the pe- organs and can also function in vegetative riphery of the parent plant with a shovel. reproduction. Fine-rooted plants, such as achillea, are 1. Bulbs—Tunicate bulbs have outer-bulb propagated from root cuttings by scatter- scales that are dry and membranous and ing 1- to 2-inch long sections of root are typical of the tulip, hyacinth, bulbous horizontally on the surface of a 2- to 3- iris, and daffodil. inch deep layer of moist soilless medium Nontunicate, or scaly bulbs, are repre- in a flat. Cover the pieces of root with 1/2 sented by the lily. These bulbs do not inch of moist sifted, soilless mix. have the dry covering, and the scales are Fleshy-rooted perennials such as baby’s separate and attached to a basal plate. breath, bleeding heart, peonies, and ori- Propagation is accomplished by periodi- ental poppies are propagated by taking cally removing the small bulbs or offsets 1 1/2- to 2-inch long sections of roots, that grow off of the main bulb. This is dusting the bottom end with a rooting usually done whenever the plants are compound, and sticking the root cutting dug. Digging of these perennials is neces- bottom end down in a 50-50 mixture of sary when the clumps become too peat moss and sand in pots or deep flats, crowded and is done after the foliage has with 1/4 inch of the cutting sticking died down naturally in the late summer or above the rooting medium. For peonies, fall. Bulbs should be planted or replanted take 3-inch long root cuttings and keep at that time. The small bulbs may need to the medium moist but not wet. When the grow for several seasons before they are cuttings begin to grow, treat them the large enough to flower. Lilies are propa- same as any other seedlings. gated by removing some of the outer 4. Layering—This is an easy way to propa- scales of the mother bulb, planting them, gate vine-type plants and ground covers. and allowing them to develop small bulbs. Bend the supple stems, without severing 2. Corms—Gladiolus and crocus are typical the stem from the parent plant, down to plants with corms. Gladiolus are the soil into a shallow trench and cover semihardy to tender in Idaho and must be several nodes with soil, or bend the stems stored overwinter in areas with severe into pots of soil. winters. The corm is a swollen base of Notching or wounding the area just be- the stem that is enclosed by dry, scaly low a soil-covered node will encourage leaves. Propagation is accomplished by rooting. Many upright plants can also be separating the small corms or cormels rooted with this technique by carefully from the mother corms. Plant these small bending their younger, more flexible corms shallowly and expect no flowers stems downward to the ground. until they grow large enough, usually 1 or 5. Grafting—This is the joining of the top 2 years. of one plant, the scion, to the bottom of 3. Tubers—These are a modified stem that another plant, the stock. This technique is serves as a storage organ. Caladium is an possible but rarely used in propagating example of a tuberous plant. Tubers can perennials. be propagated by planting the whole 6. Tissue culture—Millions of disease-free structure or by cutting tubers into sec- plants from a single small clump of api- tions, each containing one or more buds cal cells in a single season can be gener- or “eyes.” This division is done shortly ated from a tissue culture. This method is before planting.

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 13 4. Tuberous roots and stems—These thick- 2. Soil preparation—The best opportunity to ened structures are botanically different tailor the soil needs of the perennial is the from true tubers but are often called sim- first time it is prepared. Try to start soil ply “tubers.” Tuberous roots are typical preparation long before planting the bed of several types of perennials, including or border. Start in spring for a fall plant- the dahlia. Propagation is done by sepa- ing and in fall for a spring planting. This rating the tuberous roots, making sure will allow plenty of time for any organic that each root has a section of the crown soil amendments and/or pH modifications with a shoot bud. Divide in late winter or to take effect. To prepare the site for spring, shortly before planting. Tuberous planting perennials: roots are biennial, meaning the old root a. Clear all large debris from the site. disintegrates in the second year after new Kill and remove all existing vegetation tuberous roots are produced. from the site for composting. It may be Tuberous stems include the tuberous be- necessary to re-treat the site to kill per- gonia and cyclamen. These structures are sistent perennial weeds such as quack- usually vertical in orientation and have grass. vegetative buds on the upper end. These b. Spread 2 to 3 inches of organic matter tuberous stems continue to grow larger such as well-decomposed compost, and larger from year to year. Divide these aged manure, or peat moss over the structures early in the spring, making surface of the soil before beginning to sure each has a bud. work it. Rototill or spade the organic 5. Rhizomes—These specialized stem struc- matter into the soil to a depth of 8 to tures grow horizontally on top of or just 12 inches. Add no more organic matter below the soil surface. Rhizomatous iris than one-third of the final amended and lily of the valley are two perennials soil volume. Do not work the soil that can be propagated by their rhizomes. when it is wet. Organic matter incor- Remove sections of shoots and roots early poration improves soil structure by in the spring or in late summer or fall. providing the lignin that glues together D.Growing, Culture, and Maintenance the soil particles. Improved soil struc- 1. Site selection—Because herbaceous pe- ture encourages water percolation and rennials can be left in a given place for a retention, aeration, and root penetra- long period of time, proper site selection tion. Spread an organic mulch over the is critical. Most plants prefer a site that prepared bed or border. It is easier and has a fertile, well-drained, organically tidier to spread the mulch before plant- rich soil with a pH of 5.5 to 6.5. Good ing. drainage is important, especially during c. Edge the bed or border in some fash- the winter, and most soils will have to be ion. An edging will be attractive and improved. The site should receive full will help reduce the encroachment of sun or shade all day. Be sure to consider the lawn. not only the present shade, but also the 3. Planting and transplanting—While bare- future shade. Take into account the rooted perennials are best planted either growth of your trees and shrubs as well spring or fall, container-grown perennials as your neighbor’s. The site should be may be planted at any time during the flat to only slightly sloped. It should be growing season, though it is more diffi- out of the drying, stem-snapping wind cult during the drought months of July but have enough breeze to provide the air and August. Freshly dug plants are best circulation essential to minimize the slow transplanted in spring or fall but may be foliage-drying conditions conducive to moved all summer if you are careful. Pe- disease. rennials such as bearded iris, bleeding heart, peonies, and oriental poppies are

19 - 14 HERBACEOUS ORNAMENTALS CHAPTER 19 best transplanted immediately after their g. Tamp the soil firmly around the root brief dormant period after bloom. When system. Leave a berm to facilitate wa- planting herbaceous perennials: tering. Water the newly planted peren- a. Dig a hole two times the size of the nials with the starter solution. Label root spread of bare root perennials and the plants or make a map of the garden one and one-half times the size of the for future reference. root ball of container-grown perennials. 4. Fertilizing—Perennials need steady, but b. Soak the roots of bare root plants for light fertilizing first in late March to early several minutes in a starter solution of April, right after the last of the mulch is 1 tablespoon of 16-12-10 or 20-20-20 removed and growth starts. Use a 5-10-5 water soluble fertilizer dissolved in 1 fertilizer at the rate of 2 pounds per 100 gallon of water. square feet of bed space. Fertilize two c. Water the potted herbaceous perenni- more times at the same rate about 6 als with a starter solution before weeks apart. Fertilize a final time in very knocking them out of the container. late summer for fall-blooming perennials. Place your hand over the top of the pot If the perennial bed or border begins to with your fingers grasping the main lag a bit in midsummer, use a water stems, turn the pot upside down, and soluble foliar fertilizer as a boost. Foliar tap the pot rim on the edge of a hard feeding should always be thought of as surface or tap the bottom of the pot supplemental to, rather than as a substi- sharply with a planting trowel. Re- tute for, granular fertilizers. move fiber pots from perennials be- cause often pots do not decompose. Be Note: Overfertilizing, especially with nitro- sure to at least peel back the rim of gen, promotes vegetative growth at the peat pots below soil level or the rim expense of flowering and increases the will act as a wick, drying out the pot need of staking for support. and the contained soil. d. Some pot-bound plants may have to 5. Watering—Frequency is dictated by cli- have the container cut away with mate and the presence of a mulch. Water snips. Score the soil ball, making three early in the day to avoid going into the to five vertical cuts into the soil ball, evening with wet, disease-susceptible fo- top to bottom, with a sharp knife. The liage. Water thoroughly, to a depth of 8 depth of the cuts will vary from 1/2 to to 10 inches, to encourage deep root pen- 1 1/2 inches deep depending upon the etration. Soil should dry out a bit between size of the soil ball. Tease some of the watering. Waterlogged soil will encour- soil away from the top, sides, and bot- age root disease and excludes oxygen, tom of the soil ball. resulting in shallow-rooted, drought- prone, unstable plants. e. Place the plant in the planting hole, making sure that the crown of plant is 6. Mulching—Helps control weeds, reduces at the same depth as it was previously water loss, moderates soil temperature growing. changes, prevents mud splattering of foli- age and flowers, helps preserve surface f. Work some organic matter one-fourth soil structure, and adds nutrients to the to one-third by volume into the soil. soil as the mulch biodegrades. Place this mixture around the roots un- til the hole is half full. Settle the soil Winter mulch can protect perennials from around the root system by mucking it excessive cold temperatures and harmful in with the starter solution. Finish fill- thawing on freezing cycles. Apply after ing the hole with the soil-organic mat- the first cold weather has occurred and ter mixture. after the soil has frozen. Cover crowns with 2 to 6 inches of light, porous mulch.

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 15 Remove mulch in the spring or before wanted offspring of existing perennials plant growth begins. may also be considered weeds since Summer mulch can be applied after the many of them, especially those from hy- soil warms up, about 4 to 6 weeks after brid parents, will not come true-to-type. the last of the winter mulch is removed. Your first chore is to be able to distin- Try to coordinate the placement of the guish weeds, even at the seedling stage, summer mulch so that it follows one of from desirable perennials. Once so distin- the fertilizations and weed-destroying guished, weeding can be done by hand, cultivations. Apply between 1 to 2 inches with shallow cultivation, with herbicides, of mulch. Be sure to keep the mulch or largely avoided by using mulches. away from the crown of the herbaceous 10. Deadheading—Removal of spent blooms perennial. or inflorescence improves the appearance The best mulches to use are those that of the herbaceous perennials and prevents biodegrade to the point that they can be the investment of energy in seed produc- worked into the soil in late fall or early tion. It also encourages the plant to con- spring. Mulches in this category include tinue blooming, and stimulates a second compost, peat moss, or smaller-sized flush of weaker bloom in those plants bark. such as delphinium and foxglove. 7. Thinning—Removing out some of the A few perennials such as sedum ‘Autumn stems increases the potential size of the Joy’, Black-eyed-Susan, and ornamental individual blooms produced by the plant. grasses should be allowed to retain their For the most part, thinning is not neces- seed heads for their winter interest. sary as it decreases the mass of the plant 11. Disbudding—The removal of all except and may reduce the overall bloom impact the tip-most bud on each individual stem of the plant. or branch of a multibranched stem pro- 8. Pinching —Inhibits the natural legginess duces large flowers on each stem or of many perennials such as chrysanthe- branch of that stem. Peonies are often mums. Pinching the growing tips or disbudded in this fashion. The most spec- shoots of the individual stems once in tacularly sized blooms can be achieved May or June removes the inhibition of by taking a rooted cutting and limiting it the shoot tip, producing multibranched to a single terminal bud on a single stem. shoots. This produces a whole bouquet of One shortcoming of disbudding is that smaller-than-usual individual blooms. the second flush of bloom, which occurs The combined branched shoots give the after the terminal bud blooms and the ax- entire plant a much greater overall illary buds develop, is lost. Some garden- blooming mass despite the smaller indi- ers remove the terminal bud to obtain a vidual blooms. Chrysanthemums are host of relatively large axillary blooms. pinched every 3 to 4 weeks with the last 12. Staking—Giving a physical support to pinch occurring about July 15. the individual stems or to the plant as a Pinching also delays blooming. A soft whole is often necessary for those peren- pinch, just the tip of the stem, does not nials with a natural tendency to fall over delay flowering as long as a hard pinch, because of their height, habit, or weight which removes several inches and several of blooms and foliage. nodes from the stems. Pinching also de- Tall, single stems of perennials such as creases the need to stake herbaceous pe- delphiniums, gladiolus, and hollyhocks rennials as the plants are more compact. may require individual stakes for support. 9. Weeding—This is important because Select bamboo, plastic, or metal stakes weeds compete for nutrients and water. that will be at least three-quarters as tall Weeds may be grassy or broad leafed and as the individual stems they are to sup- annual, biennial, or perennial. The un- port when firmly anchored in the soil.

19 - 16 HERBACEOUS ORNAMENTALS CHAPTER 19 Tie the stems to the stakes with a figure refuse harboring insects and disease eight loop with one loop around the stake over winter. and the other around the stem. This e. Keep weeds out of the bed or border double loop acts as a spring giving the and the immediate area because they stem a chance to sway in the breeze. The are a source of both insect and disease loops can be made with paper-covered problems. wire, floral tape, or other soft material. f. Know what the most likely common Stake bushy, multistemmed, floppy pe- pests of your perennials are and then rennials such as asters, chrysanthemums, monitor for them. and coreopsis by pushing a ring of stakes g. Do not compost any diseased plants. If into the soil at a point slightly to the inte- your compost pile reaches the 140°F to rior of the perennial. Select stakes that 160°F, most disease organisms and are 6 to 12 inches shorter than the ulti- insect eggs will be killed. However, mate height of the plant. Weave a cats’ most piles never get this warm, espe- cradle of support between the stakes with cially in the outside portion. Fungus green yarn or floral tape. Start 1 foot organisms will spread along with com- above the soil level and continue upward post. at 1-foot intervals until the last cats’ h. When a problem is encountered, act cradle is 8 to 12 inches below the top of immediately without using pesticides the stems. if possible. Cut off diseased portions Alternatively, push appropriate lengths of of the herbaceous perennial, or remove multibranched tree or scrub prunings or seriously damaged plants entirely. branched bamboo canes into the soil at Handpick large insects. the fringes of the perennial. Let the inter- 14. Pesticide control—Consult with your weaving branches supply most of the county Extension educator for the most support. Some twine or floral tape may bio-rational pesticide to use for your par- still be needed to contain the stems of the ticular problem. perennials. Spot treat if possible. Use non-chemical, Place very strong, multi-legged 18- to 20- non-biological pesticides such as horti- inch tall wire hoops around perennials cultural oils and insecticidal soaps. such as peonies and oriental poppies that have very heavy blooms on supple stems. Use biological pesticides such as Bacillus thuringiensis for caterpillars, or those 13. Insects and diseases—Practices to pre- pesticides derived from natural sources vent or reduce the chance of insect and such as pyrethrum, rotenone, ryana, or disease problems include: sabadilla. When using any pesticide, fol- a. Select insect and disease-resistant pe- low the label instructions for pest con- rennials. trolled and for plants for which the b. Give your perennials the very best chemical is labeled. Always apply at the growing conditions possible from the labeled rate as instructed. Buy small standpoint of soil, nutrition, watering, quantities of the pesticide to avoid dis- spacing, sunlight, and air circulation. posal problems. c. Grow a variety of plants. A monocul- ture of a cultivar or of a few cultivars IX. A Selection of Perennials for Idaho will be far more susceptible to insect Idaho growing conditions are difficult on and disease problems. plants. During the summer, temperatures and d. Remove spent flowers, dead leaves, light intensity are high and humidity is low. and other plant litter during the grow- This combination causes some plants listed for ing season when it can be a source of the eastern United States and lower coastal el- infestation. Clean up the bed or border evations to perform poorly in Idaho. On the thoroughly before winter to avoid any following pages, Table 1 lists perennials avail-

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 17 able through the Idaho nursery trade or by so that plants can be moved into more cor- mail-order that have performed well or are rect locations in the future. A perennial deemed worthwhile for trial in Idaho. garden can be arranged and rearranged like A. Common Name—Lists several names that furniture in your home. the perennial might be called. Cross-refer- D. Bloom Time —Gives you the chance to encing is done through the text for conve- “orchestrate” and synchronize the bloom- nience. For example, hollyhock is listed ing sequence. Use a sheet of paper to list under alcea. Hollyhock is also found under and “orchestrate” your flower display. the common name, which refers back to E. Flower Color—Refers to flower colors alcea for more information. available in the nursery trade. It does not B. Scientific Name—Since the common name necessarily refer back to the specific culti- leaves a lot of guesswork, the scientific vars in the scientific name column. name is included for clarity. Under the sci- F. Light Needed—Categorizes the plant into entific name is a listing of cultivars (culti- one or more light regimes: full sun is unin- vated varieties) that may be available in terrupted sunlight through the full day; your local nursery. The cultivar name (e.g. partial shade is filtered sunlight through ‘Pink Star’) many times indicates flower tree leaves or a minimum of 6 to 8 hours of color. sunlight per day; full shade indicates fil- C. Height—Varies with fertilizer practices, tered sunlight through a dense foliage placement with respect to light, soil condi- canopy or less than 6 hours of sunlight tions, and plant vigor. A range of heights each day. is given for most plants. Determining exact G. Landscape Use—Suggests planting loca- heights will be the part of the joy of gar- tions as well as indoor uses such as cut dening. Keep records of your discoveries flowers or dried flower arrangements.

Table 1. Perennials for Idaho.

Common name Scientific name Height Bloom time Flower color Light needed Landscape use Achillea, dwarf A. tomentosa 8"-10" June-Aug Yellow Full sun Borders, ground cover (Woolly Yarrow) German hybrids, e.g., paprika Achillea, tall Achillea spp. 2 1/2'-3' June-Aug Yellow Full sun Borders, cut flowers (Fernleaf Yarrow) Partial shade dry flowers Full shade Aegopodium A. poidigrarua 8"-14" June-Aug White Full sun Ground cover, (Bishops Goutweed) variegatum Partial shade will grow in poor soil Full shade Ajuga Ajuga spp. 6"-9" April-May Blue Full sun Ground cover, edging ‘Alba’ White Partial shade rock gardens, ‘Bronze Beauty’ Full shade beneath trees ‘Gaiety’ Alcea Alcea rosea 2'-9' June-Aug White Full sun Background borders, (Hollyhock) (also Althea rosea) Yellow against fence or wall ‘Majorette’ Pink ‘Silver Puffs’ Lavender ‘Summer Carnival’ Red ’Chater’s Double Mixture’ Allium A. christophii 15"-24" Early summer Silvery-violet Full sun Herb gardens, (Stars-of-Persia or edging vegetable plots, Persian Onion) containers, edible foliage, rockeries

19 - 18 HERBACEOUS ORNAMENTALS CHAPTER 19 Table 1. (cont’d)

Common name Scientific name Height Bloom time Flower color Light needed Landscape use Allium A. giganteum 3'-4' Early summer Pink-purple Full sun Herb gardens, (Giant Onion) edging vegetable plots Allium A. karataviense 8"-10" Late spring Lilac-pink Full sun Herb gardens, (Turkestan Onion) edging vegetable plots Allium A. moly 10"-14" Late spring Bright yellow Full sun- Herb gardens, (Golden Garlic or Lily Leek) partial shade edging vegetable plots Allium A. tuberosum 20" Late summer White Full sun- Herb gardens, (Chinese Chive or Garlic Chive) partial shade edging vegetable plots Allysum A. saxatile 9"-10" April-June Golden yellow Full sun Rock gardens, dry (Basket of Gold) ‘Compacta’ walls, banks, fronts (Gold Dust) of borders Anchusa A. myosotis 6"-8" May-June Blue Full sun Borders, groupings (Forget-Me-Not) Partial shade Anemone A. blanda 3"-6" April-May Blue Full sun Rock gardens, perennial (Greek Anemone) ‘Blue Star’ Pink Partial shade borders, naturalized (Greek Windflower) ‘Bridesmaid’ Purple ‘White Splendor’ White ‘Pink Star’ Anthemis A. tinctoria 2'-3' June-Sept Yellow Full sun Perennial borders, (Golden Chamomile) ‘E.C. Buxton’ cut flowers (Golden Carguerite) ‘Kelwayi’ ‘Moonlight’ Aquilegia A. hybrida 2'-3' May-June Blue Full sun Borders, (Columbine) ‘Mckana Giant’ Pink Partial shade naturalized settings ‘Mrs. Scott Elliot’ Purple ‘Rose queen’ Red ‘Spring Song’ Yellow White Arabis A. caucasica 12" Late March White Full sun Rock gardens, dry stone (Rock Cress) ‘Snow Cap’ May Rose-tinted walls, border, small area ‘Spring Charm’ ground cover Arenaria Arenaria spp. 2"-6" May-June White Full sun Evergreen, ground (Irish Moss) Partial shade cover, rock gardens, (Sandwort) Full shade around stepping stones Armeria A. maritima 6"-15" May-June Pink Full sun Edging, rock gardens, (Sea Pink) ‘Brilliant’ White cut flowers (Sea Thrift) ‘Laucheana’ ‘Royal Rose’ Artemisia A. schmidtiana 8"-12" Foliage Full sun Perennial borders (Wormwood) ‘Silver Mound’ plant Partial shade (Angels Hair) ‘Pours Castle’ ‘Silver Brocade’ Asclepias A. tuberosa 2'-3' June-Aug Orange Full sun Borders, dry flowers (Butterfly Weed) (Pleurisy Root) Asperula A. odorata 8" May-July Pink Partial shade Ground cover, (Sweet Woodruff) Blue rock gardens White

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 19 Table 1. (cont’d)

Common name Scientific name Height Bloom time Flower color Light needed Landscape use

Aster, short/dwarf Callistephus 4"-10" Spring Many Full sun Cut flowers, (China Aster) chinensis Summer or fall bedding plants (Annual Aster) ‘Pinocchio’ ‘Dwarf Queen’ ‘Color Carpet’ Aster, tall Aster spp. or 11/2'-3' Spring Many Full sun Cut flowers, borders (New England Aster) Callistephus spp. or Summer or fall (Stokes Aster) Stokesia spp. Astilbe Astilbe x arendsii 2'-3' June-July Red Full sun Border plant (False Spirea) ‘Deutschland’ Pink Partial shade ‘Fanal’ White ‘Red Sentinel’ Aubretia A. deltoidea 6' April-May Rose-lilac Full sun Rock gardens, (False Rock Cress) ‘Bengale’ Purple Partial shade dry stone walls, ‘Purple Cascade’ Red edge of perennial borders ‘Red Cascade' Baby’s breath (see Gypsophila) Basket of gold (see Allysum) Bellflower, Chinese or Japanese (see Platycodon) Bellis Bellis perennis 4"-6" April-June White Full sun Edging, borders (English Daisy) Pink Partial shade Bergenia B. cordifolia 12"-15" April-May Pink Full sun Evergreen, rock gardens, (Heartleaf Berfenia) White Partial shade stream banks, pools, (Pig Squeak) perennial borders Betonica Stachys byzantina 6"-12" July-Oct Full sun Front of borders, (Lamb’s Ear) Partial shade ground cover, (Woolly Betony) rock gardens Bleeding Heart (see Dicentra) Campanula C. carpatica 6"-12" June-Aug Blue-lilac Full sun Borders or rock gardens (Carpathian ‘Blue Carpet’ White Partial shade Harebell) ‘China Doll’ Purple Campanula C. glomerata 1'-1 1/2' June-Aug White Full sun Borders, bedding (Danesblood) Blue Partial shade between shrubs, (Clustered Bellflower) Purple cut flowers Campanula C. medium 2'-4' June-Aug White Full sun Borders, isolated (Canterbury Bells) ‘Cup and Saucer’ Pink Partial shade clumps, balconies Blue Mauve Campanula C. persicifolia 2'-3' June-Aug White Full sun Borders (Peach Bells) Blue Partial shade Canterbury Bells ( see Campanula medium) Carnation ( see Dianthus caryophyllus) Cerastium C. tomentosum 6" May-June White Full sun Evergreen, ground (Snow-in-Summer) ‘Columnae’ cover, dry stone walls, 'Yoyo’ edging Ceratostigma C. plumbaginoldes 8"-10" July-Sept Dark blue Full sun Rock gardens, (Plumbago) Partial shade ground cover

19 - 20 HERBACEOUS ORNAMENTALS CHAPTER 19 Table 1. (cont’d)

Common name Scientific name Height Bloom time Flower color Light needed Landscape use Cheiranthus C. cheiri 9"-30" March-May White Full sun Balconies, terraces, (Wallflower) Yellow mixed borders, flower Brown beds, banks rockeries, Red slopes Pink Purple Chive (see Allium) Chrysanthemum Chrysanthemum x 2'-4' June-Oct. White Full sun Cut flowers, borders (Shasta Daisy) supermum Partial shade ‘Alaska’ ‘Esther Read’ ‘Little Miss muffet’ ‘Marconi’ ‘Snowcap’ Columbine (see Aquilegia) Convallaria C. majalis 6"-12" May White Full sun Ground cover, (Lily-of-the-Valley) Partial shade cut flowers Coral Bells (See Heuchera) Crocus Crocus spp. 2"-6" Early spring Golden yellow Full sun to Excellent for early color; & hybrids Blue partial shade Large-flowered “Dutch Lavender hybrids” bloom later than Purple most spring-flowering White types Purple striped Crocus Colchicum 4"-6" Early spring Lavender-pink Full sun to Foliage grows in spring, (Autumn) autumnale Rose partial shade then dies, flowers appear White in fall without foliage Coreopsis C. lanceolata 2'-3' June-July Yellow Full sun Borders, cut flowers (Tickseed) ‘Baby Sun’ Yellow chestnut ‘Brown Eyes’ ‘Goldfink’ ‘Mayfield Giant’ ‘Sunburst’ C. rosea C. verticillata ‘Moonbeam’ ‘Zagreb’ Creepin Jennie (see Lysimachia) Daffodil (see Narcissus) Daisy, English (see Bellis) Daisy, Gloriosa (see Rudbeckia) Daisy, Painted (see Pyrethrum) Daisy, Shasta (see Chrysanthemum) Daylily (see Hemeracallis) Delphinium D. elatum 3'-6' June-July Many Full sun Background accent, (Larkspur) cut flowers

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 21 Table 1. (cont’d)

Common name Scientific name Height Bloom time Flower color Light needed Landscape use Dianthus D. barbatus 4"-6" May-Aug White Full sun Cut flowers, balconies, Pink terraces, borders, Scarlet rockeries, flower beds Dianthus D. caryophyllus 1'-2' June-Aug White Full sun Cut flowers, flower beds, (Carnation) ‘Chabaud’s Giant Improved’ Pink pot plants, borders (Clove Pink) ‘Dwarf Fragrance Mixed’ Red (Divine Flower) ‘Enfant de Nice Mixed’ Purple ‘Juliet’ Yellow ‘Oriental Hybric Mixed’ Apricot ‘Spotti’ Orange ‘Tiny Rubies’

Dianthus D. chinensis 6"-12" Summer-fall Red Full sun Edging, cut flowers (Pinks) White Partial shade bedding Pink Dianthus D. deltoides 4"-12" May-Aug White Full sun Rock gardens, border (Maiden Pink) ‘Brilliant’ Pink plants (Meadow Pink) Red (Spink) Dicentra Dicentra spp. 2'-3' May-June Red and Partial shade Cut flowers, shaded (Bleeding Heart) white borders Digitalis D. purpurea 2'-5' May-July Purple and Full sun Borders, cut flowers (Common Foxglove) ‘Leopard Foxglove’ White Partial shade (Fairy Glove) (Fingerflower) (Purple Foxglove) Doronicum D. cordatum 2' April-May Yellow Full sun Front or middle ‘Finesse’ Partial shade perennial borders, ‘Madam Mason’ cut flowers Echinops E. exaltatus 3'-5' July-Sept Blue Full sun Cut and dried flowers (Glove Thistle) ‘Tapglow Blue’ back of borders Erigeron E. speciosus 1’-2’ June-July Blue Full sun Cut flowers, (Gleabane) rock gardens, borders Euphorbia E. myrsinites 8"-10" March-May Yellow Full sun Border plants, cut flowers, rock gardens Euphorbia E. polychroma 11/2' March-May Yellow Full sun Border plants, (Cushion Spurge) (epithymoides) cut flowers Festuca F. ovina glauca 6"-10" Full sun Edging, banks, (Blue Fescue) Partial shade ground cover Flax Linum flavum 1'-2' June-Aug Golden yellow Full sun Rock gardens (Golden Flax) Forget-Me-Not (see Anchusa) Foxglove, Common (see Digitalis) Fritillaria F. imperialis 2'-3' Spring Red Sun or A very showy (Crown Imperial) Yellow light shade old-fashioned plant, Orange but odor may be offensive

19 - 22 HERBACEOUS ORNAMENTALS CHAPTER 19 Table 1. (cont’d)

Common name Scientific name Height Bloom time Flower color Light needed Landscape use Fritillaria F. meleagris 8"-12" Spring Checkered Sun or Fragile appearance; (Checkered Lily or purple light shade makes an interesting Guinea-Hen Flower) White rock garden plant Fritillaria F. persica 10"-30" Spring Maroon Full sun Flowers have a slight (Persian Fritillary) Purple skunk odor White Gaillardia G. pulchella 1'-2' Summer Yellow Full sun Cut flowers, (Indian Blanket) ‘Baby Cole’ Fall Orange window boxes, planters Scarlet Geranium Geranium spp. 1'-2' May-Sept Blue Full sun Rock gardens, (Cranesbill) ‘Biokova’ Purple Partial shade perennial gardens ‘Johnson’s Blue’ Geum Geum spp. 2'-21/2' May-Aug Scarlet Full sun Groupings in perennial Orange borders, cut flowers Glory-of-the-Snow Chinonodoxa 3"-6" Early spring Blue Full sun Rock gardens, borders luciliae Pale pink and edgings White Yellow Gypsophila Gypsophila spp. 1'-3' June-July Rose Full sun Borders, dry flowers, (Baby’s Breath) Purple rock gardens White Pink Helianthemum H. nummularium 1' June-July Yellow Full sun Rock gardens, slopes (RockRose) Rose and pockets, crazy (Sun Rose) Red and crimson paving White Hemerocallis Hemerocallis spp. 2'-4' Spring Many Full sun Foundation plants, (Daylily) Summer Partial shade borders Fall Hen-and-Chickens (see Sempervivum) Heuchera H. sanguinea 1'-21/2' May-July Red Full sun Rockeries, borders (Coral Bells) ‘Bressingham hybids’ Pink Partial shade (Alum Root) ‘Charteuse’ White ‘Chatterbox’ ‘June Bride’ ’Matin Bells’ ‘Pluie de Feu’ (Rain of fire) ‘White Cloud’ Hollyhock (see Alcea) Hosta Hosta spp. 1'-2' July-Sept White Full sun Borders, rock gardens, (Plantain Lily) Lavender Partial shade masses Lilac Full shade Hyacinth Muscari 6"-8" Early spring Blue Full sun to Multiplies rapidly, (Armenian Grape) armeniacum partial shade excellent for edging or indoor forcing, fragrant Hyacinth Muscari botryoides 6"-8" Early spring Blue Full sun or Produces clusters of (Grape Hyacinth) White partial shade tiny flowers, double flowers hold color longer

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 23 Table 1. (cont’d)

Common name Scientific name Height Bloom time Flower color Light needed Landscape use Hypericum H. calycinum 1'-1 1/2' June-Sept Yellow Full sun Shady slopes, banks, (Aaron’s Beard) Partial shade flowerbeds, borders, (Rose of Sharon) ground cover (St. John’s Wort) Iberis I. sempervirens 6"-1' April-May White Full sun Rock gardens, edging (Evergreen ‘Autumn Snow” Candytuft) ‘Little Gem’ (Edging Candytuft) ‘Purity’ ‘Snowflake’ ‘Snowmantle’ Incarvillea Incarvillea spp. 1' June-July Red Full sun Perennial gardens, (Hardy Gloxinia) Pink rock gardens Iris 200+ species 4"-48" Spring to fall, Wide range Full sun Beyond flowers, leaves (True-Bearded) and many cultivars most May to June, provide texture, contrast (Siberian) some rebloom of colors and combinations (Japanese) Kniphofia K. uvaria 2'-4' May-Sept Red Full sun Borders, cut flowers (Red-Hot Poker) Yellow (TorchLlily) (Tritoma) (Poker Plant) Lamb’s ear (see Betonica) Lamium L. maculatum 1' April-Sept Purple-red Partial shade Shaded perennial borders, (Spotted ‘White Nancy’ White Full shade rock gardens, Dead Nettle) summer filler Lavandula Lavandula spp. 1'-3' June-Sept Purple Full sun Borders, rockeries, (Sweet Lavender) ‘Hidcote’ cut flowers, evergreen ‘Munstead’ Liatris Liatris spp. 1 1/2'-5' July-Oct White Full sun Cutting, drying, borders (Gayfeather) ‘Kobold’ Purple Partial sun (Blazing Star) Pink

Lily Genus Lilium has 2'-7' Wide range Full sun to Accent plants (Asiatic Hybrids) 100+ species June to July partial shade and many cultivars

Lily Genus Lilium has 2'-7' July Wide range Full sun to Accent plants (Trumpets) 100+ species partial shade and many cultivars

Lily Genus Lilium has 2'-7' July Wide range Full sun to Accent plants (Surelians) 100+ species partial shade and many cultivars

Lily Genus Lilium has 2'-7' July to Aug Wide range Full sun to Accent plants (Oriental Hybrids) 100+ species partial shade and many cultivars Lily-of-the-Valley (see Convallaria) Limonium L. sinatum 1 1/2'-2' June-Aug White Full sun Flowerbeds, borders, (Sea Lavender) Yellow small clumps, rockeries, (Statice) Blue cut and dried flowers Red

19 - 24 HERBACEOUS ORNAMENTALS CHAPTER 19 Table 1. (cont’d)

Common name Scientific name Height Bloom time Flower color Light needed Landscape use Liriope Liriope spp. 10"-15" Aug-Sept Purple Full sun Evergreen, borders, Partial shade perennial gardens, Full shade rock gardens Lupine L. polyphyllus 2 1/2'-5' May-July Blue Full sun Cut flowers, borders (Lupin) George Russell hybrids Purple Partial shade Reddish purple Yellow Lychnis L. chalcedonica 2’-3’ June-July Scarlet Full sun Small groupings in borders (Maltese Cross) (Jerusalem Cross) Lysimachia L. nummularia 6"-8" June-Nov Yellow Full sun Shaded slopes and (Creeping Jennie) Partial shade banks, walls, hanging (Moneywort) Full shade baskets, bag gardens, (Creeping Charlie) submerged aquarium plant Maltese Cross ( see Lychnis) Monarda M. fistulosa to 3' June-Aug Lilac Full sun Borders (Wild Bergamot) ‘Gardenview Scarlet’ Purple Partial shade White Narcissus spp. & hybrids 3"-14" Early to Yellow Full sun or Borders, shrub beds, or (Daffodil) midspring White light shade naturalized, good for cut (Jonquil) Pink flowers (Cups: yellow, white, pink, orange, or nearly red) Ostrich Fern (see Pteretis) Pachysandra P. terminalis 6"-8" May White Partial shade Ground cover, slopes, (Japanese ‘Variegata’ (Silver edge) Full shade level ground, beneath trees Pachysandra) Paeonia P. lactiflora 3' May-June Many Full sun Accent, cut flowers (Peony) Partial shade Papaver P. nudicaule 2'-4' May-June Many Full sun Borders, cut flowers (Iceland Poppy) Partial shade Papaver P. orientale 2'-4' May-June Many Full sun Borders, cut flowers (Oriental Poppy) Peony (see Paeonia) Phlox, Creeping P. subulata 6"-10" April-June White Full sun Edging, bedding, Pink Partial shade rock gardens Salmon Purple Phlox, Tall P. paniculata 2'-3' July-Sept White Full sun Borders (Summer Phlox) ‘Symons-Jeune’ Pink Partial shade (Garden Phlox) Red Blue Purple Physostegia P. virginiana 2'-3' July-Sept Rose- purple Full sun Cut flowers, back of ‘Bouquet Rose’ White wild flower gardens ‘Vivid’ Partial shade borders, informal ‘Summer Snow’ wildflower gardens

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 25 Table 1. (cont’d)

Common name Scientific name Height Bloom time Flower color Light needed Landscape use Platycodon P. grandiflorum 2' July-Sept Blue Full sun Cutting, rock gardens, (Chinese Bellflower) 'Apoyama’ Pink Partial shade borders (Balloon Flower) ‘Shell Pink’ White (Japanese Bellflower) Plumbago (see Ceratostigma) Polemonium P. caeruleum 1 1/2' May-June Blue Full sun Rock gardens, foreground (Jacob’s Ladder) ‘Blue Pearl’ Partial shade of perennial borders Poppy, Iceland (see Papaver nudicaule) Poppy, Oriental (see Papaver orientale) Potentilla P. verna 4"-6" May-Oct Yellow Full sun Ground cover Partial shade Primrose, Primula x polyantha 6"-12" April-June Many Partial shade Shaded areas in Polyanthus ‘Colossea Hybrids’ perennial borders, ‘Pacific Giants’ shaded streams Pleretis P. modulosa 3'-4' Foliage Partial shade North exposures, under (Ostrich Fern) Full shade trees or any place where light is not abundant Pyrethrum Pyrethrum spp. 1 1/2'-2' June-July Pink Full sun Rock gardens, borders, (Painted Daisy) Red Partial shade naturalizing, cut flowers White Red-hot poker (see Knipofia) Rudbeckia R. hirta pulcherrima 2-3'' July-Sept Golden yellow Full sun Cutting, background (Gloriosa Daisy) ‘Gloriosa Daisy’ Brown Partial shade (Rudbeckia x hybrida) ‘Gloriosa Double Daisy’ ‘Gloriosa Irish Eyes’ ‘Goldstrum’ ‘Marmalade’ ‘Rustic Colors’ Santolina S. chamaecy- 1' June Yellow Full sun Evergreen, rock gardens, (Lavender Cotton) parissus low hedge, carpet bedding Sapanaria S. officinalis 1' July-Sept Pink Full sun Wild gardens, (Bouncing Bet) White Partial shade rough corners (Soapwort) Saxifraga Saxifraga spp. 3"-18" June-Aug Yellow Partial shade Rock gardens, borders, White edging, potted plants Red Pink Purple Scabiosa S. caucasian 2' June-Sept Blue Full sun Borders, flowerbeds, (Caucasian ‘Butterfly Blue’ White cut flowers Scabious) ‘Pink Mist’ Mauve (Pincushion Flower) Sea lavender (see Limonium)

19 - 26 HERBACEOUS ORNAMENTALS CHAPTER 19 Table 1. (cont’d)

Common name Scientific name Height Bloom time Flower color Light needed Landscape use Sedum S. spectabile 1 1/2'-2' Aug-Oct Pink Full shade Rock gardens, borders (Showy Stonecrop) 'Autumn Joy’ Red Partial shade (Live Forever) ‘Brilliant’ White ‘Indian Chief’ ‘Meteor’ ‘Star Dust’ ‘Variegatum’ Sedum Sedum spp. 6" Aug-Oct Red Full sun Rock gardens, borders ‘Dragon’s Blood’ Partial shade Sempervivum S. tectorum 6"-30" July Purple-red Full sun Rock gardens, dry walls, (Hen-and-Chickens) edging, front of perennial (Old-Man-and-Woman) borders, carpet bedding, (Houseleeks) containers (St. Patrick’s Cabbage) Snowdrop Galanthus nivalis 6"-9" Spring White Full sun Good for borders and (Giant snowdrop) rock gardens Snowdrop Galanthus nivalis 4"-6" Early spring White Partial shade One of the earliest spring (Common Snowdrop) bulbs for rock gardens, borders, naturalizing, easy to grow, increases rapidlly Snow-in-Summer (see Cerastium) Stachys (see Betonica) Statice (see Armeria or Limonium) Sweet Lavender (see Lavandula) Sweet William (see Dianthus barbatus) Teucrium T. canadense 6" June-July Rose Full sun Edging, rock gardens (American Germander) Teucrium T. chamaedrys 4"-12" June-July Purple Full sun Edging, rock gardens, (Germander) hedges Thymus T. serpyllum 3"-6" June-July Purple Full sun Rock gardens, herb (Thyme) White gardens, stone walls Red Tradescantia T. virginiana 1 1/2'-2' June-Sept White Full sun Borders, foundations (Virginia ‘Purple Dome’ Pink Partial shade Spiderwort) Red (Widow’s Tears) Tritoma (see Kniphofia) Trollius T. europaeus 1'-2' May-July Lemon Shade Borders (Globe Flower) Orange Tulip Tulipa spp. 3"-30" Spring All colors Full sun Variety of colors, shapes, & hybrids except true blue blooming times for all uses, may use annuals to cover ground above bulbs in summer

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 27 Table 1. (cont’d)

Common name Scientific name Height Bloom time Flower color Light needed Landscape use Valeriana V. officinalis 3'-5' June-July Pink Full sun Perennial gardens, ‘Rubra’ White Partial shade background Red Purple Veronica Veronica spp. 1 1/2' June-Aug. Blue Full sun Borders, cut flowers, ‘Red Fox’ Pink rock gardens ‘Sunny Border Blue’ Red White Vinca Vinca minor 6"-8" March-May Blue-purple Partial shade Ground cover in (Lesser Periwinkle) Full shade flower beds or rockeries, (Myrtle) shrubberies

Wall Flower (see Cheiranthus) Yarrow (see Achillea)

Hudak, J. 1993. Gardening with Perennials Month Further Reading by Month. 2nd ed., revised and expanded. Timber Press, Portland, OR. Books Jelitto, L. 1990. Hardy Herbaceous Perennials. 3rd A Catalog of New and Noteworthy Fruits. 1995. ed. The Gardener’s Handbook. Vol. 3. Timber New York State Fruit Testing Cooperative Press, Portland, OR. Association, Inc., Geneva, NY. Jones, C. 1990. Perennials: The Complete Guide to A Guide to Herbaceous Perennial Gardens in the Perennials for Amateurs and Experts. Whitecap United States. 1987. Perennial Plant Association, Books, Vancouver, BC. Columbus, OH. Loewer, P. 1989. A Year of Flowers. Rodale Press, Armitage, A. M. 1993. Allan Armitage on Emmaus, PA. Perennials. Prentice Hall, New York. Lovejoy, A. 1991. Perennials: Toward Continuous Bird, R. 1994. The Cultivation of Hardy Perennials. Bloom. New Voices in American Garden Writing. Batsford, London. Capability’s Books, Deer Park, WI. Bloom, A. 1991. Alan Bloom’s Hardy Perennials. McGourty, F. 1989. The Perennial Gardener. Batsford, London. Houghton Mifflin, Boston. Fell, D., and C. Heath. 1994. 550 Perennial Garden Murray, E., and D. Fell. 1989. Essential Annuals. Ideas. Simon and Schuster, New York. Crescent Books, New York. Gorkin, N. K. 1989. Perennials: A Nursery Source Phillips, E., and B. C. Colston. 1993. Rodale’s Manual. Plants & Gardens, Vol. 44, No. 4; Illustrated Encyclopedia of Perennials. Rodale Handbook No. 118. Brooklyn Botanic Garden, Press, Emmaus, PA. Brooklyn. Phillips, R., and M. Rix. 1991. The Random House Hansen, R., and F. Stahl. 1993. Perennials and Book of Perennials. 2 Vols. Random House, New Their Garden Habitats. 4th ed. Portland, OR: York. Timber Press. Proctor, R. 1990. Perennials: Enduring Classics for Harper, P. 1990. Designing with Perennials. the Contemporary Garden. Harper and Row, Macmillan, New York. New York. Harper, P. 1985. Perennials: How to Select, Grow & Rice, G. 1995. Hardy Perennials. Viking, London. Enjoy. HP Books, Tucson, AZ. Ruggiero, M., and Clausen, R. R. 1994. Perennial Hobhouse, P. 1985. Color in Your Garden. Little, Gardening. 1st ed. The American Garden Guides. Brown and Company, New York. Patheon Books, New York.

19 - 28 HERBACEOUS ORNAMENTALS CHAPTER 19 The Best of Fine Gardening: Perennials. 1993. Booklets and Pamphlets Taunton Press, Newtown, CT. University of Idaho Extension Thomas, G. S. 1990. Perennial Garden Plants or PNW 550 Encouraging Beneficial Insects in Your the Modern Florilegium: A Concise Account of Garden Herbaceous Plants, Including Bulbs, for General Garden Use. 3rd edition, revised. Sagapress, with PNW 500 Plant Materials for Landscaping Timber Press, Portland, OR. PNW 164 Propagating from Bulbs, Corms, Tubers, Verey, R. 1990. The Art of Planting. Little, Brown, Rhizomes, and Tuberous Roots and Boston. Stems Wilson, H. V. P. 1992. The New Perennials PNW 151 Propagating Herbaceous Plants Preferred. Collier Books, New York. from Cuttings PNW 170 Propagating Plants from Seed For More Information CIS 858 Using Bark and Sawdust for Mulches, Hardy Plant Society of Oregon, P.O. Box 5090, Soil Amendments, and Potting Mixes Oregon City, OR 97045 CIS 1062 Starting a Home Lawn Northwest Perennial Alliance, P.O. Box 45574, CIS 1063 Thatch Prevention and Control in Home University Station, Seattle, WA 98145-0574. Lawns Perennial Plant Association, Attn: Dr. Steven M. PNW 299 Turfgrass Seedings: Recommendations Still, 3383 Schirtzinger Road, Hilliard, OH for the Pacific Northwest 43026. CIS 888 Weed Control in Lawns Perennial Study Group, Arboretum Foundation, Washington Park Arboretum, University of Washington, Box 358010, Seattle, WA 98195- 8010.

CHAPTER 19 IDAHO MASTER GARDENER PROGRAM HANDBOOK 19 - 29