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University of Kentucky College of , HO-102 Food and Environment Cooperative Extension Service Annual and Perennial Kentucky Master Gardener Manual Chapter 13

By Mary Robson, retired extension agent, King and Pierce counties, Washington State University. Adapted for Kentucky by Sharon Bale, extension specialist and Rick Durham, consumer horticulture extension specialist and master gardener state coordinator.

an you imagine a world without flowers? Their textures, col- In this chapter: ors, scents, and forms inspire gardeners, artists, and writers. The desire to grow flowers often motivates novices to take Types of Herbaceous Ornamental ..177 Cup gardening and moves experienced gardeners to become Using Herbaceous Perennials in Garden specialists. Annuals, biennials, and herbaceous perennials offer Design...... 179 variety and interest to all styles of gardens. Not so long ago, flowers often were separated from other parts of Flower Garden Maintenance...... 184 the garden. Masses of colorful annuals filled park and home dis- , Corms, , , and play beds only in summer. Herbaceous perennials, laid out in long Tuberous ...... 186 borders, demanded intense management without providing year- Specialized Herbaceous Flower Gardens..188 round interest. Since the 1980s, however, American had moved away from flower displays that are attractive for only a For More Information...... 189 few months, and gardeners now plan landscapes for all seasons. In today’s smaller gardens, often entirely visible from inside the home, combinations of and , , and perennial flowers keep the scene fascinating year-round. Gardens often include spring-flowering bulbs, containers of annual flowers, for cooking or tea, and grasses for winter texture. Plants in contemporary gardens are selected not only for their flowers, but for multiseason characteristics, such as form, foli- age texture, and color. Flowers remain important, but the gardening world is taking advantage of new possibilities offered by an enor- mous range of ornamental herbaceous plants. These include annu- als, biennials, perennials, and bulbs. Types of Herbaceous Ornamental Plants Annuals Annuals live briefly. They germinate, grow, bloom, and go to seed in one year. Because they die at the end of this cycle, they must be replanted the following season. Many annuals come up on their own from the previous year’s seeds. Some, such as () and bachelor’s buttons (Centaurea cyanus), can become weedy by reappearing from seed so prolifically. Whether or not this char- acteristic is desirable depends on your garden’s style. Informally designed cottage-style gardens gain from self-seeded plants, but formal gardens, which require precise balance and layout, do not, and volunteer annuals must be removed.

Cooperative Extension Service | Agriculture and Natural Resources | Family and Consumer Sciences | 4-H Youth Development | Community and Economic Development 178 • Annual and Perennial Flowers Chapter 13

Colorful, long-blooming, and easy to Biennials grow, annuals offer much to gardens. They often produce flowers or decorative Biennials often confuse gardeners. They steadily from early summer until they set require two full years to complete their seed or are killed by frost. Annuals are growth cycle and die after the second year. particularly useful for colorful window The first year, they grow foliage and roots boxes, container plantings, hanging baskets, but do not flower. The second year, they and school or youth gardens. Their quick flower and go to seed. Their garden uses growth from seeds or transplants is gratify- are closer to those of annuals than perenni- ing for young gardeners. als, but many are cherished components of Some cool-season annuals such as pan- perennial gardens. sies ( wittrockiana) and ornamental Some biennials are spectacularly showy kale (Brassica spp.) can be planted in fall because the inflorescence (flower stalk) can to replace summer annuals in containers, be huge, as on the gray-leafed window boxes, and gardens. Table 1 lists the olympicum, which reaches 8 or 9 feet tall. heightand bloom color of common annuals. Foxgloves ( purpurea), forget-me- nots (Mysotis sylvatica), and hollyhocks () are common biennials. Table 1. Height and bloom color of common annuals. Provide undisturbed space for biennial Height plants, because they require a summer (inches) Bloom color growing season and before flow- African daisy 6 - 12 White, yellow, salmon ering. Many biennials need winter protec- Ageratum 4 - 24 Blue, white Amaranthus 48 - 96 Red, red and green tion in cold . Some gardeners start Arctotis 24 White with bluish eye biennials in a nursery bed and move them Aster (Callistephus chinensis) 18 Yellow, pinkish red, blue, to permanent positions in their second year white, lavender when they are ready to flower. bacopa 6-10 White, blue Know how to identify the first-year Balsam ( balsamina) 12 - 18 , purple, white leaves (the vegetative stage) to avoid pulling , purple (foliage) 15 Red-purple foliage the plants as weeds before their second- 6-12 Pink, red, white year flowering period. Browallia 8 - 12 Blue, violet, white In some cases, newer cultivars of some 12 - 24 Yellow, gold, orange biennials have been bred to produce Cabbage, flowering 8 - 14 Red to white blooms the first season. Hollyhock ‘Queeny Calilbrachoa 6-12 Various Purple’ and digitalis ‘Camelot’ are just two Castor bean (foliage) 72 - 96 Red, inconspicuous flowers examples. When choosing a plant, be sure Capsicum 6-24 Red, orange, purple fruit Cockscomb (Celosia) 18 - 36 Blue, red, yellow, orange to read the information about that particu- Cornflower(Centaurea cyanus) 36 Pink, blue, white lar cultivar. Coleus (foliage) 8 - 20 Variegated foliage Cosmos sulphureus 18 - 24 Red, orange, yellow Perennials Cosmos bipinnatus 48+ White, lavender Unlike annuals and biennials, perennial Dusty miller (Artemisia stellerana) 24 Silvery foliage, yellow flowers plants live year after year. and shrubs Evolvulus ‘Blue Daze’ 6-10 Blue Fan flower(Scaevola aemula) 6-8 Blue, white are woody perennials. Mature garden, park, Forget-me-not () 12 Blue, pink and arboretum landscapes often are com- Four o’clock (Mirabilis) 24 Pink, white, yellow posed mostly of woody perennial plants. Gaillardia pulchella 15 - 24 Yellow, orange, red Many familiar garden flowers are peren- 12-18 pink, red, white, salmon, nials, such as (Paeonia spp.) and lavender Shasta daisies (Leucathemum maximum). continued on next page Chapter 13 Annual and Perennial Flowers • 179

These plants are called herbaceous because Some hardy perennials may live for several they do not form permanent woody branch years in this area and then mysteriously die structures as do shrubs and trees. when no obvious disease or insect prob- Hardy perennials live through winter lem is apparent. This type of death is often in the ground, reviving from their crowns attributed to the “weather.” When we have in spring. They send up new , often wide temperature fluctuations during the through the remains of the previous year’s winter, the hardiness of the plant may be dead stems, leaves, and flowers. Some affected. perennials, such as peonies (Paeonia spp.), Tender perennials won’t survive outdoor may survive for decades, long outliving the winter conditions even with protection. gardener who planted them. Some may They must be lifted before frost, stored, and only live a few years in the garden, if at alll. replanted after danger of freezing weather It is very important to choose perennials passes. , gladiolus, and tuberous that are appropriate for the location’s hardi- , are just some examples. ness zone and general conditions. How a perennial is classified depends on the climate zone the plant is being grown in. For example, a in an Table 1. Height and bloom color of common annuals. annual in Kentucky. In southern Florida it Height has become an invasive perennial. When Plant (inches) Bloom color purchasing perennials look for those plants Gomphrena 12 - 36 Lavender, purple, red, white that are hardy in Zone 6 or less. Some parts Heliotrope 10 Rose of Kentucky are Zone 7 but plants that are Impatiens 8 - 24 Red, pink, white, orange labeled as Zone 7b may have some hardi- Lantana 12-36 Red, yellow, white, lavender ness problems. Licorice plant 6-10 Grey, lime-green Lobelia 4 - 18 Blue, violet, white, pink Mandevilla Pink Using Herbaceous Perennials Marigold () 8 - 48 Yellow, orange to red-brown in Garden Design Melampodium 24 Yellow Mimulus 12 - 30 Yellow, red Because perennials reappear year after Nicotiana 24 - 48 Red, pink, white year, they have advantages over annuals. Nigella 12 - 15 White, blue, violet The plants can fill space rapidly if grown in Pansy (Viola) 8 - 12 Blue, purple, white, yellow proper conditions. Many reach their mature Petunia 6 - 12 White to rose, purple size several years after planting, expand- Portulaca 8 Yellow, white, rose, orange ing gradually into large, showy clumps. 18 - 36 Blue, red, white There are hundreds of different perennials, Salvia farinacea (Mealycup sage) 14-18 Blue, white each with a distinct texture, color, scent, Snapdragon (Antirrhinum) 6 - 18 Blue, purple, yellow, orange, red and form, which makes choosing plants an Statice, () sinuatum 18 - 24 Yellow, rose, violet, white intriguing adventure. Strawflower(Helichrysum) 36 White, red, yellow Most perennials bloom for a fairly short Sunflower() 12 - 108 Yellow to red-brown time, from one to three weeks, although Sweet alyssum (Alyssum 3 - 10 White, purple some, such as (Coreopsis verticil- maritimum) lata), can bloom persistently for as long as Sweet vine vine Green, purple six weeks. Careful perennial plant selec- Tithonia 48 Orange tion can provide garden interest from early Torenia 12 White, blue, violet spring to frost and even through winter. 8 - 24 White, pink, blue, red 8-12 White, lavender, pink Zinnia 6 - 36 Red, pink, yellow, orange, white, lime green 180 • Annual and Perennial Flowers Chapter 13

Table 2. Bloom season, height, and bloom color of common perennials.* Italian arum () is an exam- Height ple of a plant that produces winter interest. Botanical name Common name (inches) Color The foliage appears in late fall and persists Late winter, spring over the winter. The bright orange-red ber- Chionodoxa luciliae glory-of-the-snow 4 blue ries that are produced on strong stems also Crocus (species and crocus 4 various provide color well into the winter. hybrids) Successful flower gardening depends, Endymion hisipanicus Spanish bluebell 12-15 blue, white as does any other aspect of gardening, hyemalis winter aconite 3 yellow on understanding your site’s character- nivalis common snowdrop 6-12 white istics and matching them to the needs of Helleborus (species and Lenten rose 15-18 various individual plants. Annual and perennial hybrids) flowers have been hybridized for centu- Hyacinthus orientalis hyacinth 12-14 various ries, chosen from wild plants originating sempervirens candytuft 3-6 white in bogs, sunny , alpine meadows, danfordiae danford iris 4-6 yellow woodland shade, and many other grow- Leucojum vernum spring snowflake 10-12 white virginica Virginia bluebells 12-14 blue ing conditions. Understand your garden armeniacum hyacinth 6-8 blue environment before selecting herbaceous pseudonarcissus narcissus, daffodil varies various plants. Analyze the hours of daylight, soil siberica Siberian squill 3-6 blue texture, drainage, water availability, and Tulipa (species and varies various winter frost conditions. Choose plants that hybrids) have cultural needs matching your garden’s characteristics. Late spring, early summer For a low-maintenance perennial garden, Achillea filipendulina -leaf yarrow 24-36 yellow consider several basic plant characteristics: Amsonia tabernaemontana amsonia 12-36 blue (hybrids) columbine varies various • Is the plant long-lived (lasting at least Aurinia saxatilis basket-of-gold 12 yellow four seasons)? Armeria maritima common thrift 6-12 pink • Does it grow strongly but not overwhelm Astilbe arendsii astilbe 24-36 various other plants? Baptisia australis false indigo 36-48 blue • Will it have a long bloom time? Brunnera macrophylla heartleaf brummera 12-18 blue • Is it attractive when out of bloom? glomerata clustered bellflower 12-18 blue, • Is it generally pest-resistant? purple Convallaria majalis 10-12 white, pink Peonies (Paeonia spp.), purple cone- barbatus sweet William 10-18 various flower ( purpurea), and Autumn Dianthus gratianapolitanus cheddar pink 9-12 rose, pink Joy (Sedum spectabile ‘Autumn Joy’) Dicentra spectabilis common bleeding heart 18-24 pink are among the many herbaceous perennials odoratum sweet woodruff 4-9 white that meet these criteria. Heucherella tiaraelloides foamy bells 15-24 pink Hemerocallis (hybrids) daylily varies various Garden design (which should be based Iris (hybrids) tall bearded iris 12-24 various on harmonious color patterns), bloom Siberian iris 24-36 various throughout the seasons, and intriguing Leucanthemum x superbum shasta daisy 18-24 white year-round texture depend on the gar- Paeonia suffructicosa varies various dener’s taste. Because herbaceous plants are Paeonia (hybrids) peony varies various used intensively in modern gardens, many orientale Oriental 18-36 various books have excellent suggestions on how Phlox subulata moss phlox 6-9 various to design with them. Visiting gardens and nurseries and keeping an idea notebook also will help you develop design confi- continued on next page dence and improve your garden choices. Chapter 13 Annual and Perennial Flowers • 181

Table 2. Bloom season, height, and bloom color of common perennials.* Table 2 lists perennials by season of Height bloom and gives their height and bloom Botanical name Common name (inches) Color color. Figure 1 illustrates how plants can be Summer arranged according to height, while Figure 2 shows arrangement by season of bloom. common yarrow 12-18 various tuberosa butterfly weed 24-36 orange Figure 3 is an example of a garden design Coreopsis grandiflora tickseed 12-24 yellow that combines perennial and annual flowers thread leaf coreopsis 18-36 yellow with a variety of bloom seasons, colors, purple coneflower 24-36 purple, heights, and textures. various Echinops ritro globe thistle 12-36 blue Selecting Plants Heliopsis helianthoides sunflower heliopsis 36-48 yellow, orange Select annual and perennial plants for Heuchera sanguinea coral bells 12-18 red the best possible growth qualities. The Hosta (species, hybrids) hosta 6-36 purple, popularity of flower gardening encour- white ages plant hybridizers and growers to offer Liatris spicata spike gayfeather 24-36 mauve improved plants with more vigor, larger Limonium latifolium sea lavender 24-30 lavender flowers, longer bloom periods, and more Iris kaempferi Japanese iris 34-30 various attractive leaves. For instance, pansies have (species, hybrids) lily varies various been selected for color and form, produc- Perovskia atriplicifolia Russian sage 48+ blue tion of pink flowers, orange/purple com- garden phlox 36-48 various fulgida orange coneflower 18-30 yellow binations (Viola wittrockiana ‘Jolly Joker’), and diminutive yellow forms as well as the Late summer and early fall familiar, large, purple-whiskered faces. Anemone x hybrida Japanese anemone 24-36 white, pink When a design specifies a particular Aster novae-angliae New England aster 48+ violet, plant, look for cultivars that may have purple improved characteristics over the parent Aster novi-belgii Michaelmas daisy 12-48+ violet plant. Often this means seeking a named purpureum Joe-Pye weed 48+ purple variety rather than simply a straight species. Sedum spectabile showy stonecrop 12-24 pink Tricyrtis hirta common toad-lily 24-36 lilac Association garden sales, specialty nurser- ies, mail-order catalogs, and knowledge- *Bloom times are only an estimate because location and spring temperatures can cause plants to bloom earlier or later than expected. able local gardeners are good sources for extraordinary plants.

Figure 1. Flower border divided into bold plant groupings Figure 2. Flower border designed for continuous bloom from according to height. Background: large groups of tall plants. spring through fall. Foreground: shallower, wider groupings of small plants. 182 • Annual and Perennial Flowers Chapter 13

Figure 3. Sample perennial/annual bed with a mix of bloom seasons, flower Spread 3 to 4 inches of organic material colors, and heights. In spring, blocks 1, 2, 3, 4, and 5 will bloom. In summer, blocks 4, 6, 7, 8, 9, 10, 11, and 12 will bloom. A=Annual; P=Perennial. across the soil surface and dig it in well. This addition will help increase the soil’s water-holding capacity and improve penetration and aeration. Commercial compost, homemade compost, chopped or composted leaves, composted sawdust, fine , and composted manure make good amendments. 1. Tulip (P): spring; color varies; 8–24" Recognize that many perennials form 2. Da odil (P): spring; shades of white or yellow; 8–24" large, heavy root structures, which can rot 3. Hyacinth (P): spring; pink, white, purple; 8–12" if the site isn’t well-drained, particularly 4. Pansy (A, late winter planting): winter, spring; blue, if there is a high water table in winter. If purple, white, yellow; 8–12"; Ageratum (A, June planting after pansy is nished): summer; blue, you face this situation, improve drainage white; 4–24" or choose plants suitable for damp condi- 5. Candytuft (P): spring; white; 12" tions (for instance, cardinal flower Lobelia[ 6. Dwarf marigold (A): summer; yellow, orange to cardinalis]). red-brown; 8–12" 7. Zinnia (A): summer; red, pink, yellow, orange, Soil testing is helpful when starting a gar- white; 6–36" den on an unfamiliar site or when expand- 8. Dusty miller (P): summer; silvery foliage, yellow ing an existing garden. Many herbaceous owers; 24" perennials grow well in slightly acid soil, 9. Salvia (A): summer; blue, red, white; 18–36" 10. Cockscomb (A): summer; blue, red, yellow, orange; but some need supplemental lime if the soil 18–36" pH is below 6.0. A soil test will provide a 11. Larkspur (A): spring, summer; blue, pink, recommendation for adjusting the pH if it is white; 18–36" required. Generally, sulphur can be added 12. Globe (A): summer; white, pink, purple; 15–30" to lower the pH and lime can be added to increase the pH. Propagation Soil Preparation Annuals and biennials If you follow some sensible basic steps These flowers generally are started from when installing a new garden, you’ll have seed or are purchased as small plants. Many good results. For perennial gardens, soil annual seeds can be sown directly in the preparation is a key to strong future growth. garden. For annuals that are hard to trans- Later applications of fertilizer can’t com- plant, such as Shirley poppies (Papaver pensate for poorly prepared soil. rhoeas), direct seeding is necessary. When First, get rid of weeds, especially perenni- choosing flowers for children’s gardens, als such as quackgrass, dandelions, morning seeds such as nasturtiums ( glory, and thistles. Then dig thoroughly, majus) and sunflowers (), loosening the soil to at least 12 inches. which sprout quickly and are large enough (Double-digging often is recommended for to handle, inspire satisfaction. herbaceous perennial gardens. This pro- Many other annuals and biennials do cess involves digging 20 to 24 inches deep, best if started in a propagation bed or tray loosening the soil, and moving the top layer and then transplanted as small plants. down about one shovel’s depth. This prac- Marigolds (Tagetes spp.), violas and pansies tice increases air and nutrients available to (Viola spp.), and snapdragons (Antirrhinum roots and can produce a fine garden site majus) transplant well. Start seedlings capable of sustaining plants for many years.) indoors four to six weeks before they will be Chapter 13 Annual and Perennial Flowers • 183

planted in the garden. Provide ample light, The proper time to divide perennials using auxiliary light if necessary, to grow depends on the particular plant. In general stocky, healthy transplants. Beware of start- divide fall-blooming plants such as aster ing seedlings too early; they grow poorly (Aster spp.) in very early spring. Spring if left too long in low light and crowded bloomers such as iris (Iris spp.) can be indoor conditions. divided in late summer or early fall. Buying seedlings from nurseries is very Select vigorous shoots from the outer convenient, especially for annuals with very part of a clump. Discard the center. Divide fine seeds, notably petunias, impatiens, and the plant into several sections of three fibrous begonias. Unless you have excellent to five shoots each. Make large divisions, propagation facilities, plants are difficult to because small pieces will not bloom much grow from fine seed. the first year after planting. Before replant- ing, add compost or other organic materials Perennials to the soil. Perennials grow more slowly than annu- Cuttings—Many plants can be propagated als, and many do not bloom the first year, from either tip or root cuttings. Generally, although some will. You can start them tip cuttings are easier to grow than root from seed in a nursery bed and transplant cuttings. them to a final location when they are Take 2- to 6-inch-long tip cuttings from sturdy enough. Often they are ready to perennials such as candytuft (Iberis sem- transplant late in their first season. pervirens) or lavender ( angus- Keep in mind that starting perennials tifolia and others). Remove all foliage from from seed can be a slow process and may the lower one-third of the cutting. Insert require waiting several years before any cuttings in a clean planting mix such as one- blooms appear. The cost of purchasing half sharp sand and one-half peat moss. perennials is often directly related to the Professional growers supply bottom heat number of years the plant has been in pro- and provide moisture through automatic duction. While some of the newer cultivars misting systems that keep cuttings moist of certain perennials have been bred to while roots form. If you don’t have these produce blooms the first season from seed- systems, rooting will be slower and require ing, others require several years of growth more care, but you still can be successful. before any blooms will be produced. Cover cuttings with a sheet of clear plastic Division—As herbaceous perennials to retain moisture. Support the plastic to develop established root systems, they keep it from touching the foliage. Place the spread into large clumps, so many can be cuttings in a light area but out of direct sun. propagated by division. In direct sun, high temperatures can build Divide perennials as part of your general up under the plastic on warm days and can garden maintenance, because growth and kill cuttings. performance decrease when plants get When cuttings resist a slight tug, they crowded. Centers die out on many plants, have begun to root. The plants then start to such as Siberian iris (Iris siberica). Division take up water and nutrients. Poke holes in rejuvenates plants and results in extra the plastic to provide more air circulation plants to share with friends or donate to to the rooting plants, gradually adding holes plant sales. as more roots grow. When the plants have formed good root balls, transplant them to a nursery bed or container and begin fertilizing. 184 • Annual and Perennial Flowers Chapter 13

Root cuttings also work to propa- Weeding gate some plants, such as Oriental pop- pies (Papaver orientalis), phlox (Phlox Keep annuals and perennials free of paniculata), and baby’s breath ( weeds. A combination of hand weeding paniculata). Dig plants in late summer after and is effective. Weed regularly to they have bloomed and are going dormant. prevent seeds from becoming established. Choose pencil-sized roots and cut them Herbaceous plants shade out some weeds into 4-inch sections. Shoots will not appear when mature but require extra vigilance until the following growing season. while they are too small to compete. Use with great care in herba- ceous plantings, if at all. Always read the Flower Garden Maintenance label of any before using. The label will list plants that will not be damaged as Regular, planned maintenance keeps well as list those plants that may be severely plants healthy and a garden looking damaged by that particular chemical. Use attractive. them only around woody plants established in the landscape for more than six months. Fertilizing It’s best to remove annual weeds at the Annuals need regular fertilizing. Well- seedling stage by hoeing lightly, avoiding prepared soil and organic mulch help make the roots of desired plants. You can spot- nutrients available to plants, but annuals treat persistent perennial weeds such as grow so rapidly that supplemental fertilizer morningglory with a postemergent herbi- helps. When planting, incorporate about cide such as glyphosate (sold as Roundup 5 pounds per 100 square feet of 5-10-5 or and many other trade names), but take 5-10-10 fertilizer. Then fertilize at regular great care to keep herbicides off the leaves intervals, about every three weeks. Don’t of all desirable plants. add fertilizer to dry soil; be sure to water before and after fertilizing. Watering When planting a new perennial garden, Most annuals need regular water add about 5 pounds of 5-10-5 or 5-10-10 because they don’t make deep root systems. per 100 square feet and dig it in thoroughly However, some annuals, such as cosmos before planting. Fertilize established herba- (Cosmos bipinnatus), tolerate summer dry ceous perennials as they start growth each spells. year. Perennial plants that bloom in late Do not allow herbaceous perennials to summer or fall, such as asters, need regular dry out in their first season. Many tolerate fertilization before bloom, so feed them dry soils once established, however. Interest monthly until September. Perennials such in water conservation causes many garden- as peonies that complete their bloom and ers to choose plants that need little supple- growth by June do not need fertilizer in mid- mental water. Plants such as artemisia, summer. In general, two light applications of echinacea, Jerusalem sage (Phlomis spp.), fertilizer per year are sufficient for supplying and santolina use only moderate amounts extra nutrients if soil conditions are good. of water. Always water after applying fertilizer. To use water efficiently, group plants according to water needs. Till the soil deeply and amend it with compost or other organic material. When you water, use efficient methods such as soaker hoses or drip irrigation sys- tems, and apply water slowly and deeply. Chapter 13 Annual and Perennial Flowers • 185

Mulching break these plants’ stems and ruin the dis- play. Broken stems also can lead to disease Organic mulch is useful in perennial and problems. annual flower beds. Use compost (commer- Many short perennials such as peo- cial or homemade), composted sawdust, nies require support to keep flower heads chopped or composted leaves, or other upright. A plant that flops over onto adjoin- materials for mulching. ing plants will smother its neighbors and Two applications of mulch each year destroy a garden’s attractiveness. are helpful. Apply 2 to 3 inches in spring Commercial systems such as grates with after weeding and fertilizing to retain soil legs work fine, but you also can improvise moisture, suppress annual weed seeds, supports from stakes, twigs, or and improve the bed’s appearance. Apply branches. Choose staking material that mulch again in late fall. As it breaks down is about 6 inches shorter than the plants’ over winter, this material will provide some ultimate height. winter protection and weed suppression. Whatever method you use, put support Do not cover a perennial plant’s crown systems in place while plants are small and (the central growing area above the roots) tie plants loosely to the stake as they grow with winter mulch, but do bring it up to (Figure 4). Rapid growth will hide the stake, the edge of the crown. In cold locations, wires, or strings. you can cover the entire plant after the soil freezes or after several freezing nights. If you cover plants too soon, they may begin Deadheading and Disbudding to grow under the mulch and may be killed Regular maintenance for annuals by severe cold. Evergreen boughs make includes removing flowers before they go to a good mulch, particularly in cold winter seed. This process is called deadheading. By areas. preventing seed formation, you can extend Pull mulch off plants in early spring the bloom period on many plants, such as when weather warms, allowing new growth pansies, marigolds, and petunias. to emerge. Deadheading not only might prolong the bloom period, but it improves a gar- Staking den’s appearance. Some early summer- blooming perennials such as certain daylilies Many tall herbaceous flowering plants (Hemerocallis spp.) produce a second flush of must be tied to stakes or provided with flowers in fall if stems are cut to the ground another support system, especially in windy after bloom and before seeds set. In other and exposed areas. Dahlias, for example, cases, however, seeds may be part of the gar- may require support. Wind, rain, or the den show. Gladwin iris (Iris foeditissima), for weight of foliage and blossoms will bend or example, is grown for its showy seed pods.

Figure 4. Staking plants: In (a) and (b), plants are tied too tightly. In (c) and (d), principal branches loosely. which is better.

(a) () (c) (d) 186 • Annual and Perennial Flowers Chapter 13

Plants such as dahlias produce larger Slugs and snails attack tender shoots of flowers if disbudded. A stalk may have five bulbs, lilies, and young transplants and are or six buds; to disbud, snap off all but one often a problem where hostas are planted. on each stem. Hand picking and selective use of baits can help you manage slugs. Place baits in traps Fall Cleanup rather than broadcasting them. Late fall maintenance generally includes Consult relevant publications and cutting back dead stems of herbaceous experts for specific controls. Make sure you perennials and pulling out annuals after have properly identified the problem before they are killed by frost. Some gardeners applying any control. leave seed heads for birds. Goldfinches love cosmos seeds, and chickadees eat sunflower Bulbs, Corms, Rhizomes, seeds right off the plants if squirrels don’t get them first. The seeds of many perennials, Tubers, and Tuberous Roots such as purple coneflower Echinacea( pur- Many garden plants are classified purea), attract birds in late summer and fall. botanically as bulbs, corms, rhizomes, tubers, or tuberous roots. All of these have Pest Management underground organs that store food for the All flower gardens eventually have some plant. Many, such as hyacinths, , and pests or diseases. Learn to use the principles crocuses, can survive for a time without of integrated pest management and concen- soil around their roots, which enables them trate on growing healthy plants. Strong plants to be stored and shipped easily. Figure 5 resist disease and insect problems better than illustrates flowers of several types of bulbs weak ones. To reduce disease infestations and corms. and cut down on hiding places for insects Bulbs are composed of a thin, flattened and other pests such as slugs, space plants stem surrounded by fleshy, dried leaf bases properly to allow good air circulation, clean called scales. Roots grow from a basal plate. up litter and dead leaves, and control weeds. , garlic, narcissus, tulips, and lilies Several diseases commonly affect annu- are examples of plants that form bulbs. als, bulbs, and herbaceous perennials. Slicing an vertically and observing Powdery mildew (a fungus) attacks peonies, the interior gives a good look at a ’s zinnias, , pansies, and many other anatomy. flowering plants, producing a gray, fuzzy Corms have solid interiors, developed coating on leaves and blossoms. Tulips, from swollen stems. If you cut one, you see lilies, and peonies contract botrytis, which a homogenous mass inside. Roots form at affects buds and stems and destroys flower- the base. Some examples of plants that form ing. Pruning out diseased plant parts can corms are crocus, watsonia, and gladiolus. help control this disease. Tubers are swollen, modified, under- Whenever possible, choose disease-resis- ground stems. They don’t have basal plates tant cultivars. Check with nurseries for new where the roots originate. Tubers come in cultivars of phlox and bee balm () various shapes and include caladium. with powdery mildew resistance. Tuberous roots are composed of root Some insects damage a wide variety of tissue. Dahlias and tuberous begonias are plants. For example, aphids suck juices from examples of plants with tuberous roots. many flowering plants. Learn the life cycles Rhizomes are specialized stems that of garden pests so that you can protect ben- grow horizontally at or just below the soil eficial predators and minimize use of broad- surface. German iris, lily-of-the-valley, and spectrum insecticides. Aphids, for example, bamboo have rhizomes. have many natural enemies, including lady beetles, lacewings, wasps, and birds. Chapter 13 Annual and Perennial Flowers • 187

Gardeners often lump these different Selection and Storage botanical structures under one heading, call- ing them all “bulbs.” This loose classification Choose solid, healthy plants. With lil- works for general purposes, but the distinc- ies, tulips, and narcissus, larger bulbs yield tions between the types make a difference in larger blossoms. Some bargain bulbs are not how each is propagated and stored. worth the price, no matter how inexpensive, Like other herbaceous ornamentals, because they are too small to bloom well. bulbs, corms, and tubers are classified as Purchase hardy bulbs in the fall. Don’t hardy or tender. Most hardy bulbs and leave bulbs in a hot car trunk while shop- corms are planted in fall for early spring ping; the plants may be damaged or killed. bloom. Crocuses, narcissus, tulips, hya- If you can’t plant bulbs immediately, keep cinths, and grape hyacinths define spring them cool and dry. Temperatures below for many people. Lilies, which bloom in 65°F are best for storage. Use paper sacks early or midsummer, may be planted in fall rather than plastic bags, since mold may or early spring. develop if moisture accumulates inside the Tender bulbs, tubers, and corms gener- package. ally bloom in mid-to-late summer. Examples After digging plants such as dahlias and are dahlias, tuberous begonias, and gladiolus. cannas in the fall, store them in slightly Plant them when the ground warms after the damp peat or perlite. Do not let them com- last frost. To keep these plants for more than pletely dry out; check them regularly and one season, dig them up in the fall and store dampen them if necessary. them in a frost free location.

Figure 5. Bulbs and corms offer a variety of blossoms.

Galanthus (Snowdrop) Eranthis (Winter aconite) Anemone blanda Iris reticulata giganteum 36 Crocus Grape hyacinth imperialis Hyacinth 30 Tulip (early) Da odils Tulips 24 (midseason) Tulip (late)

18 Height (inches) Height

12

6

5” 8” Planting depth

very early spring early spring mid-spring late spring Bloom time 188 • Annual and Perennial Flowers Chapter 13

Site Preparation and Planting Fertilize spring bloomers when they are about an inch tall, using a 5-10-10 granular Drainage is vital for most bulbs, corms, formula or a liquid fertilizer. In dry areas, tubers, rhizomes, and tuberous roots. With water spring-blooming bulbs after flower- a few exceptions, such as Japanese iris (Iris ing ends. Let the leaves wither naturally and ensata), they rot in wet soil. Snowdrops don’t pull them out until they are brown. (Galanthus nivalis), crocuses, narcissus, Move spring-blooming bulbs and corms tulips, and lilies must have excellent drain- only after all foliage has ripened (usually in age. If your garden site drains poorly, place late summer). bulbs in containers or raised beds. Dig the soil as for annual or perennial flowers and add organic amendments such Specialized Herbaceous as compost. Remove all perennial weeds Flower Gardens before planting, and watch for emerging annual weed seedlings after planting. Specialized herbaceous flower gardens When planting, excavate the planting include container plantings, bog gardens, area, place fertilizer below the root level, and water gardens. and mix it thoroughly with soil. Slow- release fertilizers or general 5-10-10 formu- Container Plantings lations work well for fall-planted bulbs. Do Almost all gardeners have some form not place bulbs directly on fertilizer. of container plantings, often in addition to Don’t plant bulbs and tubers in dry soil; other types of gardens. Containers allow roots cannot begin to grow without mois- even those with limited space such as a ture. If the soil is very dry during fall plant- rooftop, balcony, or front stoop to have ing, dig a hole for the bulbs, fill it with water, vigorous gardens. and allow it to drain before planting. The potting material contributes vitally Planting depth depends on soil condi- to the success of container plants. Plant tions. Kentucky extension publications or roots must get sufficient air. If the soil is too local nurseries can give you specific sugges- dense, it packs down, contributing to root tions. Many growers suggest planting about rot or other difficulties. Be sure to use a pot- three times the depth of the bulb. ting material that contains sufficient gritty Shallow-planted bulbs may frost-heave particles in the form of pumice, perlite, or and are easily dug out by rodents, which vermiculite. Garden soil doesn’t work well munch on them. To prevent rodent dam- in containers because watering packs it and age, plant them in a hardware cloth “cage.” reduces available oxygen. Mulch hardy bulb and corm plantings Choose a container suited to the plant’s lightly with 2 to 4 inches of composted eventual size, and be sure it has sufficient leaves, shredded fir bark, or composted drainage holes in the bottom. Scrub pots sawdust. Keep open and light well. Do not add a layer of gravel or other enough to allow shoots to emerge in spring. material to the bottom of the pot; this prac- tice actually reduces drainage. Fill the clean Watering and Fertilizing pot full of potting soil. After planting, be sure to water the You can reuse potting mixes year after planting bed thoroughly and continue to year unless the plants in them were seri- water during periods of dry weather in the ously diseased. Before replanting, dump the fall. Fall-planted bulbs begin to produce a mix out of the pot, aerate it, and add new root system and lack of water may severely grit if necessary. damage the bulbs. Annuals grown in containers will require more frequent fertilization. Regular water- ing will leach the initially applied nutrients from the soil. Follow the package directions Chapter 13 Annual and Perennial Flowers • 189

for slow release fertilizers. An additional. Armitage, A.M. Herbaceous Perennial application may be necessary mid way Plants: A Treatise on Their Identification, though the growing season. If water soluble Culture, and Garden Attributes, 3rd ed. fertilizers are being applied follow the label (Stipes Pub Lic., 2008). recommendations for how frequently this Bloom, A. Alan Bloom’s Hardy Perennials should be applied. Remember, plants grown (Batsford, London, 1991). in containers will require regular water- Eyewitness Garden Handbooks: Perennials, ing. When watering plants be sure to water 1st American ed. (DK Publishing, New thoroughly and then allow the plants to dry York, 1996). out before watering again. Smaller contain- Elliott, J. The Smaller Perennials (Timber ers such as hanging baskets may require Press, Portland, OR, 1997). watering twice a day to maintain vigor Hansen, R., and F. Stahl. Perennials and during the heat of the summer. Generally, Their Garden Habitats, 4th ed. (Timber the larger the container the less frequently it Press, Portland, OR, 1993). will need to be watered. Harper, P. Designing with Perennials (Macmillan, New York, 1990). Bog and Water Gardens Harper, P., and F. McGourty. Perennials: How to Select, Grow, and Enjoy (HP Small fountains, pools, and other water Books, Tucson, 1985). features are increasingly popular in gardens. Hartmann, H.T. Plant Propagation: Many herbaceous perennials adapt well to Principles and Practices, 7th ed. (Prentice water gardening. A pool can be surrounded Hall, Englewood Cliffs, NJ, 2001). with Japanese iris (), ligularia Hobhouse, P. Color in Your Garden (Little, (Ligularia dentata), rodgersia (Rodgersia Brown, and Co., New York, 1985). podophylla), and adapted native plants. A Lloyd, C., and G. . Garden Flowers from barrel with a fountain bubbler can hold Seed (Timber Press, Portland, OR, 1994). water lilies, many of which are winter-hardy, Macunovich, J. Caring for Perennials: even in cold climates. What to Do and When to Do It (Storey Some gardeners place a simple, shal- Publishing, Pownal, VT, 1997). low bowl of water in the garden to reflect Phillips, R., and M. Rix. The Random House the sky. Water features also attract wildlife, Book of Perennials, 2 vols. (Random especially birds. House, New York, 1991). Raven, S. The Cutting Garden: Growing For More Information and Arranging Garden Flowers (Frances Lincoln, Pleasantville, NY, 2006). UK Extension Publications Rix, M. Growing Bulbs (Timber Press, HO-65, Annual Flowers Portland, OR, 1986). HO-76, Perennials for Sunny Locations Thomas, G.S.Perennial Garden Plants or HO-77, Perennials for Shady Locations the Modern Florilegium, 3rd ed., revised HO-80, Spring, Summer, and Fall Bulbs (Sagapress, with Timber Press, Portland, Books OR, 1990). Wilson, J.W. Landscaping with Container Armitage, A.M., Armitage’s Manual of Plants (Houghton Mifflin, Boston, 1990). Annuals, Biennials, and Half-Hardy Perennials (Timber Press, Portland OR, Periodicals 2001). Fine Gardening www.finegardening.com Armitage, A.M., Armitage’s Garden Annuals Garden Design www.gardendesign.com (Timber Press, Portland OR, 2004) Gardens Illustrated www.gardensillustrated. com Horticulture www.hortmag.com 190 • Annual and Perennial Flowers Chapter 13

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