Flowering Perennials: Characteristics and Culture
Revised by David Trinklein
Horticulture Extension State Specialist
Division of Plant Sciences & Technology
A perennial plant is one that lives two or more years. By definition, herbaceous perennials are nonwoody plants whose above-ground parts usually die to the ground each year. They survive winter weather by means of a vigorous root system, bulbs, corms, tubers, rhizomes or other underground root or stem modifications. Several shrubs that often die back to the ground each year are frequently grouped with herbaceous perennials even though they are technically woody plants. Roses, tree peonies and Russian sage are examples of flowering shrubs more frequently considered flowering perennials. Even though they are woody plants, they regrow vigorously each year from the root system if harsh winter weather causes a complete dieback.
Herbaceous perennials can be further subdivided into hardy and tender plants, based on the plant's ability to survive the winter. Examples of hardy perennials are tulips, lilies, daylilies, peonies and irises. Tender perennials include dahlias, gladioluses and cannas. While it may seem a misnomer to classify a nonhardy plant as a perennial, the presence of a storage organ (e.g., a corm or tuber) puts a plant into the herbaceous perennial category.
Herbaceous perennials are considered the backbone of most flower gardens. Plants provide almost year-round interest with a variety of flower color, form, foliage, texture and fragrance. Careful planning can ensure a succession of bloom that provides a changing kaleidoscope of color through the seasons.
Figure 1. Because perennials are less formal than annuals, they often are used in border plantings such as the one pictured above.
The pages of this guide list some major perennial plants and their important characteristics and cultural preferences.
Space is not available here to fully describe the plants and flowers. Reviewing garden websites or visiting a nursery, garden center or botanic garden will help you become familiar with available plants.
|18–30||Sept.–frost||W, P||SS||WD||L||M||Dislikes transplanting. Spring plant only.|
|Anthemis, Golden Marguerite|
|12–24||Aug.–frost||Y||FS||WD||L||M||Attractive fine-cut leaves. Divide every 3 to 4 years. Self-seeds readily.|
|9–36||Aug.–Sept.||W, Y||FS||WD||SL||E||Many species and varieties, including Silver Mound and Silver King.|
|Aster, Michaelmas daisy|
|12–72||July–frost||W, R, B, L, V, P||FS||M, WD||L||M||Many varieties of differing growth habit. Divide every other year.|
|12–24||May–June||W, P||FS||M, WD||L||E||Easy to grow. Good companion plant to hosta.|
|18–30||June–July||W, P||FS||WD||L||E||Easy to grow. Avoid acid soil. Add lime if necessary.|
|18–24||May–Aug.||B, W, P||FS||WD||S||M||Weak-stemmed plant, may need staking. Avoid wet soil.|
|12–18||May||Y||FS||WD||S||M||Gray foliage. Suitable for rock garden.|
|6–28||June–July||P, R, L||FS||WD||S||M||Avoid acid soil. Fairly short-lived. Some good as cut flower.|
|18–24||July–Aug.||R, P, L, W||FS||WD, D||L||M||Useful for hot, dry places. Also endures light shade.|
|8–36||May–July||W, B||FS, SS||WD||SL||M||Needs good drainage. Avoid clay. Mulch in winter. Species vary in height.|
|12–15||May–June||P, W||SS||M||L||M||Waxy foliage remains green in winter.|
|24–36||July–Aug.||O||FS||WD||L||E||Flowers followed by blackberry-like seed pods.|
|24–36||June–July||Y, O||FS||WD||L||E||Very heat tolerant. Good for bold splash of color.|
|Bleeding heart, Old-fashioned|
|18–24||May||P, R||FS, SS||WD||L||M||Best in part shade. Leaves may die-back in summer.|
|Blue false indigo, Rattle weed|
|36–48||May–June||B||FS||WD||SL||E||Forms dark pods with large seeds that rattle.|
|12–28||June–Aug.||B||FS||WD||L||E||Short-lived. Easily grown from seeds planted in spring.|
|24–48||Aug.–Sept.||W, P||FS||WD||L||E||Choose named cultivars. Species gets too tall for most gardens.|
|Brunnera, Siberian bugloss|
|12–18||May–June||B||SS||M, WD||L||M||Flowers resemble forget-me-not.|
|12–20||Aug.||O, Y, R||FS||WD||SL||E||Difficult to transplant. Suited to hot, dry sites. Attracts monarch butterfly.|
|8–12||April||W||FS||WD||L||M||For rock garden and stone walls.|
(Chrysanthemum x morifolium)
|10–36||July–frost||W, R, O, V, L, P||FS||WD||L||E||Variety determines growth habit. Pinch tips of tall types in early summer to promote bushiness.|
|6–36||April–June||W, R, P, V, B, L, Y||FS, SS||WD||SL||E||Fairly short-lived. Reseeds easily. Sow seeds in early summer.|
|24–36||Aug.–Oct.||P||FS||WD||L||E||Tolerates very poor soil. Heat and drought tolerant.|
|18–24||June||W, P, R||FS, SS||WD||L||M||Divide every 3 years. Good cut flower.|
|Coreopsis, Thread-leaf tickseed|
|18–30||June–Aug.||Y||FS, SS||WD, M||L||E||Easy to grow. Blends well with other perennials. Blooms all summer.|
|15–36||June–Sept.||R, O, Y, L, P||FS, SS||WD, M, D||L||E||Easily grown. Adapts to many conditions. Excellent hybrids available.|
|36–60||July–Aug.||W, B, L||SS||WD||L||M||Likes cool weather. Give afternoon shade. Needs excellent drainage.|
|8–36||July–Aug.||Y, P||FS||WD||SL||M||Flowers open in evenings. Good rock garden plant. Some can be invasive.|
|18–48||July–Sept.||P, W||FS, SS||M, WD||L||E||Also called obedient plant. Very vigorous grower.|
|36||July–Sept.||Y, O||FS||WD||L||M||Flowers good for cutting.|
|10–12||May–June||W, P||SS, S||WD||L||M||Compact, spreading growth habit. Flowers similar to Astilbe.|
|24–28||June||V, P, W||SS||M, WD||L||M||Grow as biennial. Prefers cool temperatures.|
(Gaillardia x grandiflora)
|24–30||July–Sept.||Y, R||FS||WD||L||M||Easy to grow. Heat tolerant.|
|12–20||July||R, O, Y||FS||WD||SL||M||Divide every 3 years. Provide winter mulch.|
|24–48||July–Sept.||B||FS, SS||WD||SL||E||Tolerates poor soil. Replant every 3 to 4 years.|
|12–18||May||Y, O||FS, SS||M, WD||L||M||Do not let dry out. Good beside pools.|
|24–36||July–Aug.||W||FS||WD||L||E||Very aggressive. May become invasive.|
|36–48||Aug.–Oct.||Y, R||FS||M, WD||L||E||Good cut flower. Divide and replant every 3 years.|
|24–60||July–Sept.||W,P, R||FS||M, WD||L||M||Very large flowers. Tolerates damp soil.|
|48–72||July–Aug.||W,P, R||FS||WD||L||E||Grown as biennial. Seed outdoors in July.|
|Hosta, Plantain lily|
|6–36||July–Aug.||W, L||SS, S||M, WD||L||E||Excellent for shady areas. Many have variegated leaves.|
|Iris, Bearded, German iris|
(Iris x germanica)
|12–36||April–June||B, V, R, P, W, Y, L, O||FS||WD||L||E||Easy to grow. Many varieties available. Very dependable and easy to grow.|
|18–36||June–July||B, W, Y, L, P||FS, SS||M, WD||L||M||Needs moist soil. Suitable at the edge of ponds.|
|18–24||May–June||W, B||FS, SS||M, WD||L||E||Likes rich soil. Never let dry out.|
|12–18||June||P||FS, SS||WD||SL||M||Will grow in dry, poor soils. Woolly grayish leaves.|
|10–12||June–July||Y||FS, SS||M||L||M||Compact, spreading habit. Prefers a cool, moist location.|
|12–20||July–Aug.||L||FS||WD||SL||M||Needs well-drained soil. Very fragrant foliage.|
|8–12||Aug.–frost||B||FS||WD||SL||E||Sometimes called plumbago. Semiwoody groundcover.|
|5–8||Feb.–March||W||SS||M, WD||L||C||Needs rich soil. Do not disturn root system.|
|24–48||July–Sept.||W, L||FS||WD||SL||E||Adapts well to dry locations. Spike florets mature from top downward.|
|6–10||Aug.||V, W||FS, SS, S||WD||L||E||Evergreen border plant. Forms clumps. Cut back old growth in early spring.|
|6–8||May||W, P||SS||M, WD||L||E||Needs shade. Used as a groundcover or cut flower.|
|18–30||July–Sept.||Y||FS, SS||M, W||L||E||Needs semi-shade in dry soils. Can be invasive.|
|8–12||May–June||B||SS, S||M||L||M||Very distinctive foliage with unusual variegation.|
|24–40||June–July||B, W, P, Y||FS, SS||WD||SL||C||Dislike hot summers. Short-lived in Midwest.|
|24–30||June–July||P, V, W||FS, SS||M, WD||L||M||Needs afternoon shade. Prized for foliage and flowers.|
|24–36||June–July||W, P||FS, SS||WD||L||E||Fleecy, graceful flowers. Prefers humus-enriched soil.|
|Painted daisy, Pyrethrum|
|12–24||June–July||P, R, W||FS||WD||L||C||Will not tolerate wet soils. Prefers cool temperatures.|
|6–10||April||B, W||FS||WD||SL||M||For rock garden. Needs good drainage. Blooms early.|
|18–36||May–June||W, P, R||FS, SS||WD||L||E||Very long-lived. Huge, elegant flowers.|
(Salvia x superba)
|18–24||June–July||B, V, P||FS||WD||L||E||Effective blue flower color. Attracts bees.|
|3–5||April–May||P, L, W||FS||WD||SL||M||Also called ground pink or thrift. Tolerates poor soil.|
|18–48||June–Sept.||R, P, L, W||FS, SS||WD||L||M||Many varieties available. Blooms mid-summer.|
|18–24||June–July||B||FS||WD||L||M||Unique blue flower with conspicuous stamens.|
|10–15||May–July||R, W, P||FS||WD||L||M||Very fragrant. Bluish gray foliage. Edging plant.|
|4–9||May||R, P, W||FS||WD||L||M||Dwarf pink. Gradually spreads to form a green mat.|
|8–12||June||R, O, P, W||FS, SS||WD||SL||M||Often grown as annual. Seeds started indoors will flower first season.|
|24–40||May–July||O, R, P, W||FS||WD||SL||E||Needs good drainage. Place in protected spot, or mulch in winter.|
|Red-hot poker, Tritoma|
|36–48||July–Sept.||O, Y, P, W||FS||WD||SL||E||Needs excellent drainage. Mulch in winter.|
|5–10||June–July||P, W||FS||WD||SL||M||Pruning back helps retain compact form. Needs good drainage.|
|36–48||June–July||B||FS||WD||L||E||Uniquely colored, aromatic foliage. Light blue flowers that attract bees.|
|15–24||Aug.–Sept.||B, W||FS||WD||SL||M||Large foliage. Delicate blue flowers on large panicles.|
|4–24||June–frost||P, R, Y, W||FS||WD||SL||E||Very heat and drought tolerant. Many species with varying heights.|
(Leucanthemum x superbum)
|12–36||June–Aug.||W, Y||FS||WD||L||M||Somewhat short-lived in garden. Dwarf and tall forms available.|
|3–5||May–June||W||FS||WD||SL||M||Small gray woolly leaves. Forms dense carpet. Needs excellent drainage.|
|8–24||May–Aug.||B, V, W||SS, S||M, WD||L||E||Easily grown. Bright blue flowers. Native plant.|
|12–30||Aug.–Sept.||B, W, P||FS||WD||L||M||Needs good drainage. Mulch in winter.|
|Sweet pea, Perennial|
|60–96||June–Aug.||P, R, W||FS, SS||M, WD, D||L||E||Very easy to grow. May crowd out other plants.|
|6–15||May–June||R, P, W||FS||WD||L||E||Biennial that self-sows easily. An “old-fashioned” favorite.|
|8–12||June–July||P, V, W||FS||WD||SL||E||Needs good drainage. Mulch in winter.|
|24–36||June–July||Y, O||FS||WD||L||E||Tolerant of dry soils. Good for low maintenance areas.|
|2–36||May–Sept.||B, W||FS||WD||L||E||Easy to grow. Species differ in growth habit.|
|6–8||April–May||V, L, W, Y||FS, SS||WD, M||L||E||Forms a dense mat. Reseeds easily. Can be invasive.|
|2–36||June–Aug.||Y, P, R, W||FS||WD||L||E||Easy to grow. Delicate aromatic foliage.|
|20–30||June–July||W||FS||WD||L||E||Very durable. Bears huge spike with white flowers.|
The height range, given in inches, helps to determine whether a plant is suitable for an edging (1–12 inches), for the middle of a bed (12–36 inches), or for a background plant (more than 36 inches). Where a very wide range is given (such as Bellflower, 8–36 inches), some dwarf varieties are indicated.
The month or months of peak bloom are listed. Time of flowering varies with exposure and climatic area. These listings are primarily for central Missouri.
Plants are keyed with their most common colors. Many blends, shades and tints exist.
- Blue (B)
- Green (G)
- Lavender (L)
- Orange (O)
- Pink (P)
- Red (R)
- Violet (V)
- White (W)
- Yellow (Y)
- Full sun (FS)
Locate plant away from the shade of buildings, large trees or other objects that will not allow at least six hours of direct sunlight each day.
- Semi-shade (SS)
Give partial shade either as a long period of light shade or as more dense shade during the afternoon. Most plants in this category must have shade during the hottest part of the day.
- Shade (S)
These plants must have continuous shade with no direct sun. In heavy shade, other necessary cultural requirements must be carefully fulfilled.
- Well drained (WD)
Periods of standing water on the soil are damaging to perennials in both summer and winter. In heavy soils, add liberal amounts of organic matter to ensure good internal soil drainage. If external drainage is poor, consider raised beds or drain tile below. For information on improving soils, see MU Extension publication G6955, Improving Lawn and Landscape Soils.
- Dry (D)
These plants will not tolerate moist conditions very long, but they will withstand considerable dryness.
- Moist, but well drained (M)
Plants in this category do not tolerate drying, but they also do not tolerate any water standing around their roots. In the garden, they need regular watering during dry periods.
- Wet (W)
Plants will tolerate boggy conditions or even standing water. However, they are not the aquatics, such as waterlilies. Aquatic plants are not included in this publication.
- Loam (L)
Any good well-kept garden soil fits this category. Yearly additions of organic matter help develop a good loam. Where a poor soil is to be planted for the first time, amend it by mixing in at least 4 inches of organic matter.
- Sandy loam (SL)
This type of soil is required mainly by plants that need excellent drainage. If the original soil is a tight clay, large amounts of sand will have to be added to achieve this type of soil.
- Easy (E)
- Moderate (M)
- Challenging (C)
Unusual or outstanding plant and cultural characteristics are listed briefly. Included are notes on cultural ease, winter hardiness, or special uses, or emphasis of an extremely important cultural requirement.
Garden chrysanthemum. Garden phlox.