Cool Season Annuals HORT 308/609 Assigned Readings for Plant List 6 Plant List 6 Spring 2020 Read the pages in your textbook associated with the family descriptions and individual taxa covered on Plant List 6 that was distributed in lab. These plant lists are also available on the course website All Text And Images Are Copyrighted By: Dr. Michael A. Arnold, Texas A&M University, Dept. Horticultural Sciences, College Station, TX 77843-2133 Cool season flowers Cool Season A bit of landscaping helps Annuals most any structure! • Tolerant of freezing to subfreezing temperatures – Suitable for use throughout winter in southern half of our region – Suitable for late fall and very early spring use in northern portions of the region • Provides off-season color in winter Cool season foliage Cool (Season) Thoughts Alcea rosea • Many species are derived from edible or Hollyhocks medicinal European species • Classic old-fashioned reseeding annual, • Plants utilized solely for foliage are biennial, or weak perennial more common than with other • Tolerates cold to USDA z. 5, but heat of z. 8 is tough seasonal annuals • Tall cool season annuals are infrequent, • Bold coarse textured foliage; rounded mound the or become tall only late in the season first year or winter and then stiffly upright in spring • Limited range of soil moisture is common • Most decline when day temperatures consistently exceed 80°F or night temperatures exceed 70°F • Mostly for detail designs, bedding, or seasonal containers • Miniature hibiscus-like flowers – Singles quaint, doubles more formal Antirrhinum majus peony or carnation-like appearance Snapdragon – Flower stalks 3’ to 10’ depending on the site conditions and cultivar selected • Cool season annual cut flower or bedding plant in southern parts of our region – Colors vary from white, pink, red, to Rust fungi • Fairly frost tolerant, transition annual in purple, rarely pale yellow northern parts of our region • Cotton root rot, spider mites, • 3” - 8” terminal racemes of pea-like flowers rust fungi, Japanese beetles – White, pink, red, orange, yellow, purple, • Cottage gardens, strong vertical 2-tones; cyclic flushes on short types accent, spring borders • 6” rounded mound to narrow upright & 5’ tall Alcea rosea Hollyhocks Antirrhinum majus Snapdragon • Sun to part shade, well drained moist soils; sun for bloom – Prone to rots and mildew in wet sites What is wrong • Summer heat and drought intolerant with this • Bedding, edging, containers, baskets, cut flowers Antirrhinum majus? Linaria spp. Linaria spp. Toadflax Toadflax • Informal version of Snapdragon; 12”-18” tall; • Native species have pale blue to white flowers • Exotics add multiple colors; early spring bloom • Wildflower mixes, informal borders, early color • Wildflower mixes, informal borders • Fall seed in south; late winter transplants north • Finer textured & even earlier bloom than snapdragons; best as masses not individuals Brassica oleracea Color without flowers? var. acephala Ornamental Cabbage Ornamental Kale • Cool / cold season vegetable crop; variegated & dissected foliage types for landscape use – Green, white, red, purple combinations – Ruffled, dissected, 8” - 18” rosette of foliage Cabbage looper damage Brassica oleracea var. acephala Brassica oleracea var. acephala Ornamental Cabbage or Kale Ornamental Cabbage or Kale • Bolts (elongating flower spikes in spring) – Creamy white to pale yellow flowers, + or - – Bolting signals end of useful life – Fairly cold tolerant, remove immediately if cold damaged, rotting foliage produces a foul odor; rotate beds to avoid diseases / pests • Bedding, formal designs, accents, containers • Brassica oleracea var. capitata = head form This sometimes happens when you get a warm spell in late winter? Brassica juncea Beta vulgaris var. cicla Giant Mustard Not for flowers Ornamental Swiss Chard • Ornamental Cabbage or Kale alternative • Coarse textured bold rumpled rugose foliage 1’ to 2’ tall • Handsome coarse bold colorful winter foliage; edible, but not always palatable • Dark purple-bronze leaves contrast sharply with lighter veins • Bronze, blue-green, to dark green blades contrast with white, pink, purple, • Vigorous and good cold tolerance red, yellow or orange stalks and veins (ok in DFW); good in containers • Use seed blends to retain color diversity • Effective cool season massing plant or in herb, cottage or kitchen garden Beta vulgaris var. cicla Lactuca sativa Ornamental Swiss Chard Lettuce • Same species as edible beet; produces edible • Classic edible green possessing a foliage, but does not form an edible root variety of foliage forms, textures, and • Full sun for best color; treat as an annual colors with ornamental potential • Can be effective in cold of USDA z. 6 • Taller (18”) than many cool season color to 8, but is not heat tolerant plants; coarse bold texture • Lots of foliage pests, but a very rapid grower; lush temporary filler plant • Cottage garden; educational gardens; accent plantings; container gardens Lactuca sativa Cynara cardunculus Lettuce Cardoon • 1’-2’ (3’) tall coarse textured blue- • Excellent example of a dual purpose plant which could be incorporated in green to silver-green mound of sustainable landscapes foliage in winter • Conventional production, hydroponics of • Bolting to 5’ to 6’ in spring many forms, containers or even living wall culture can all be significant • Strong accent / background plant • Also effective for attracting wildlife Cynara cardunculus Calendula officinalis Cardoon Pot Marigold • Iridescent blue thistle-like flowers • Herb, cottage, heritage gardens • A classic cottage garden plant • Close relative of Globe Artichoke, grown for medicinal purposes, Cynara scolymus; z. 8 (7)-10 (11) later converted for ornamental use; dual purpose plant • Daisy to Zinnia-like, yellow to orange flowers • Intensely bright to more pastel cultivars Calendula officinalis Cyclamen persicum Pot Marigold Florist’s Cyclamen • Cool to transition season annual • Red, pink, white, to purple flowers atop • Powdery mildew, slugs, and spider a dense mound of violet-like foliage mites are periodic problems • Unique inverted flowers held above • Sunny site in well drained moist soil foliage • Bedding (variable sizes available), • Long season of effectiveness massing, or cut flower gardens; cottage and children’s gardens; • Effective for bedding, containers, detail medicinal gardens; patio containers work, cool high light interiorscapes Cyclamen persicum Cyclamen persicum Florist’s Cyclamen Florist’s Cyclamen • Shade to morning sun; needs moist rich soils; not heat or drought tolerant • Tubers can be lifted & stored in cool & dry location in summer • Summer dormancy • Cool season annual USDA z. 9 & warmer What caused this problem? Dianthus chinensis Dianthus chinensis China Pinks China • Short-lived perennials used Pinks as cool season annuals – Effective fall - early summer in TX • Best in rich organic – Popular summer annual in central and northern regions of USA soils, but tolerates less fertile sites • Short, 6” - 12” tall, compact • Crown rot in wet mound, medium / fine texture soils, melts in • Profusion of white, pink, red Texas’ summer or two-tone flowers heat – Color range & size are expanding • One of best cool – Peak spring bloom, some flowers season color plants fall and winter for Texas Eschscholzia californica Eschscholzia californica California Poppy California Poppy • Outstanding as a cool season annual • Use in sunny • Sprawling mound 1’ to 2’ tall site with well drained soils, • Rich green / blue-green finely dependable if winters are not divided foliage contrasts with too cold bright orange flowers • Excellent accent, massing, informal beds, naturalizing • Expanding range of flower colors • Rotate plantings due to Sclerotinia root & crown rots Eschscholzia californica subsp. Papaver spp. mexicana is native to El Paso area Poppies • Group of species used in warm climates as cool or transition season annuals or as herbaceous perennials in cooler climates • Most with a rosette-like growth form until flowering commences when stalks elongate • Most species are planted Vistas in foothills of Franklin Mountains near for the large 3” to 6” El Paso, Texas courtesy of Dr. Geoff Denny diameter cup-shaped or peony-like flowers Papaver spp. Lathyrus odoratus Poppies Annual Sweet Pea • Short, 6’ to 8’ tall, weakly climbing to sprawling blue-green vine with tendrils • Pea-shaped blue, pink, red to white fragrant spring flowers; fruit inedible • Flowers come in a variety of • Rare cool season trellis / fence cover, fragrant cut flowers; naturalizing iridescent colors and petals have a tissue-paper like texture • Tolerate frost, but not hard freezes • Place in sun, well drained soils, foliage dies down in summer • Source of pharmaceuticals and illegal drugs; also culinary uses Limonium sinuatum Lobularia maritima Annual Statice Sweet Alyssum • Low growing 4” to 6” tall • Cool to transition annual; low flat rosettes of spreading cool to transition foliage with 1’ to 2’ stalks topped by wind- season annuals; summers in north sweep 4”- 8” long x 1”- 2” wide inflorescences • Long bloom season of white, pink, • Showy white, pink, pink-orange, purple, to maroon fragrant flowers lavender, yellow, or blue calyx • Root rots in poor soils & takes limited heat, otherwise trouble-free • Tall bedding, accent, cut or dried arrangements • General bedding, rock gardens, living walls, containers, edging, detail work, fragrance gardens ‘Snow Princess’ Matthiola incana Matthiola incana