Flowering Perennials: Characteristics and Culture

Reviewed by David H. Trinklein
Division of Plant Sciences
Mary Kroening
Missouri Master Gardener Program

Flowering perennials represent a large group of garden plants with roots that persist from year to year. Stems and leaves of some may remain, but in most, the tops die back to the soil each winter.

Perennials are suitable for many locations. Most frequently, they are incorporated in a flower border that they share with annual flowers and shrubs. Perennials with similar cultural requirements are grouped into plantings known as rock gardens, wildflower gardens, bog gardens or perennial flower borders.

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 catalogs or visiting a nursery, garden center or botanic garden will help you become familiar with available plants.

Mixed borders of perennials Figure 1
Mixed borders of both perennials and herbaceous perennials can provide an interesting landscape year-round.
 

Description of terms and codes

Height

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.

Bloom period

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.

Color(s)

Plant 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)

Cultural requirements

Light

  • 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.

Moisture

  • 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.

Soil

  • 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 (at least 50 percent) of sand will have to be added to achieve this type of soil.
  • Organic soil (OS)
    Some plants require a soil very high in organic materials that have an acid reaction. Where soils are not naturally this way, liberal amounts (up to 33 percent) of peat moss mixed thoroughly with the soil can achieve this condition, and annual applications of sulphur may be necessary for maintenance.
  • Woodland soil (WS)
    Such a soil is usually required for the wildflower garden. It results from decomposition of leaves and is fairly high in organic matter. It is not necessarily very acid soil. Add liberal quantities of leaf compost or peat to prepare this type of soil.

Relative ease of care

  • Easy (E)
  • Moderate (M)
  • Challenging (C)

Remarks

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.

Table 1. Characteristics and culture of flowering perennials.

Common name,
Scientific name
Height
(inches)
Bloom
period
ColorLightMoistureSoilRelative
ease
Remarks
Anemone, Japanese,
Anemone japonica
18–30 Sept.–frost W, P SS WD L M Dislikes transplanting. Spring plant only.
Anthemis, Golden Marguerite,
Anthemis tinctoria
12–24 Aug.–frost Y FS WD L M Attractive fine-cut leaves. Divide every 3 to 4 years. Self-seeds readily.
Artemisia,
Artemisia sp.
9–36 Aug.–Sept. W, Y FS WD L, S E Many species and varieties. Includes Silver King and Silver Mound.
Aster, Michaelmas daisy,
Aster hybrids
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.
Astilbe,
Astilbe sp.
12–24 May–June W, P FS M, WD L E Easy to grow. Sometimes incorrectly called spirea.
Baby’s breath,
Gypsophila paniculata
18–30 June–July W, P FS WD L E Easy to grow. Avoid acid soil. Add lime if necessary.
Balloon flower,
Platycodon grandiflorum
18–24 May–Aug. B, W, P FS WD S M Weak-stemmed plant, may need staking. Avoid wet places.
Basket-of-gold,
Aurinia saxatile
12–18 May Y FS WD S M Foliage gray. Suitable for rock garden.
Beardtongue,
Penstemon sp.
6–28 June–July P, R, L FS WD S M Avoid acid soil. Fairly short-lived. Some good as cut flower.
Bee-balm,
Monarda didyma
18–24 July–Aug. R, P, L, W FS WD, D L M Other species available. Useful for hot, dry places. Also endures light shade.
Bellflower,
Campanula sp.
8–36 May–July W, B FS, SS WD S M Needs excellent drainage. Avoid clay. Mulch in winter. Species vary in height.
Bergenia,
Bergenia cordifolia
12–15 May–June P, W SS M L M Waxy foliage remains green in winter.
Blackberry lily,
Belamcanda chinensis
24–36 July–Aug. O FS WD L E Flowers followed by blackberry-like seed clusters.
Black-eyed Susan,
Rudbeckia fulgida
24–36 June–July Y, O FS WD L E Very tolerant. Good for bold splash of color.
Bleeding heart, Old-fashioned,
Dicentra spectabilis
18–24 May P, R FS, SS WD L M Easy to grow. Should be fall planted.
Blue false indigo,
Baptisia australis
36–48 May–June B FS WD S, L E Also called rattlebush. Missouri native.
Blue flax,
Linum perenne
12–28 June–Aug. B FS WD L E Likes poor soil. Lasts about 3 years. Easily grown from seeds planted in spring.
Boltonia,
Boltonia asteroides
24–48 Aug.–Sept. W, P FS WD L E Choose named cultivars. Species gets too tall for most gardens.
Brunnera, Siberian bugloss,
Brunnera macrophylla
12–18 May–June B SS M, WD L M Resembles forget-me-not.
Butterfly weed,
Asclepias tuberosa
12–20 Aug. O, Y, R FS WD S E Difficult to transplant. Suited to hot, dry sites.
Candytuft, Evergreen,
Iberis sempervirens
8–12 April W FS WD L M For rock garden and stone walls, or groundcover.
Chrysanthemum,
Dendranthema hybrids
10–36 July–frost W, R, O, V, L, P FS WD L E Varieties determine growth. Pinch tips of tall types in early summer for bushiness.
Columbine,
Aquilegia hybrids
6–36 April–June W, R, P, V, B, L, Y FS, SS WD S, L E Fairly short-lived. Reseeds easily. Sow seeds in early summer.
Coneflower, Purple,
Echinacea purpurea
24–36 Aug.–Oct. P FS WD L E Tolerates very poor soil. Flower “petals” drooping.
Coral bells,
Heuchera sanguinea
18–24 June W, P, R FS, SS WD L M Divide every 3 years. Good cut flower.
Coreopsis, Thread-leaf tickseed,
Coreopsis verticillata
18–30 June–Aug. Y FS, SS WD, M L E Easy to grow. Blends well with other perennials. Blooms all summer.
Daylily,
Hemerocallis hybrids
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.
Delphinium,
Delphinium hybrids
36–60 July–Aug. W, B, L SS WD L M Likes cool weather. Give afternoon shade. Needs excellent drainage.
Evening primrose,
Oenothera sp.
8–36 July–Aug. Y, P FS WD S, L M Flowers open in evenings. Good rock garden plant. Some are invasive.
False dragonhead,
Physostegia virginiana
18–48 July–Sept. P, W FS, SS M, WD L E Also called obedient plant. A vigorous grower.
False sunflower,
Heliopsis helianthoides
36 July–Sept. Y, O FS WD L M Flowers good for cutting.
Foamflower,
Tiarella cordifolia
10–12 May–June W, P SS, S WD L M Compact, spreading growth habit. Flowers similar to Astilbe.
Foxglove,
Digitalis purpurea
24–28 June V, P, W SS M, WD L M Grow as biennial. Sow seed in coldframe in Aug. or Sept. A cool-climate plant.
Gaillardia,
Gaillardia x grandiflora
24–30 July–Sept. Y, R FS WD L M Easy to grow. Good cut flower.
Geum, Avens,
Geum hybrids
12–20 July R, O, Y FS WD S M Divide every 3 years. Provide winter mulch.
Globe thistle,
Echinops ritro
24–48 July–Sept. B FS, SS WD S, L E Tolerates poor soil. Replant every 3 to 4 years.
Globeflower,
Trollius europaeus
12–18 May Y, O FS, SS M, WD L M Do not let dry out. Good beside pools.
Gooseneck loosestrife,
Lysimachia clethroides
24–36 July–Aug. W FS WD L E Very aggressive. May become invasive.
Helenium, Sneezeweed,
Helenium autumnale
36–48 Aug.–Oct. Y, R FS M, WD L E Good cut flower. Divide and replant every 3 years.
Hibiscus,
Hibiscus palustris
24–60 July–Sept. W,P, R FS M, WD L M Also called H. moscheutos. Flowers very large.
Hollyhock,
Alcea rosea
48–72 July–Aug. W,P, R FS WD L E Best grown as biennial. Seed outdoors in July.
Hosta, Plantain lily,
Hosta sp.
6–36 July–Aug. W, L SS, S M, WD L E Useful as groundcover. Leaves large in some types.
Iris, German,
Iris germanica
12–36 April–June B, V, R, P, W, Y, L, O FS WD L E Easy to grow. Many varieties available.
Iris, Japanese,
Iris kaempferi
18–36 June–July B, W, Y, L, P FS, SS M, WD L M Suitable at the edge of ponds. Replant every 4 to 5 years.
Iris, Siberian,
Iris siberica
18–24 May–June W, B FS, SS M, WD L E Likes rich soil. Never let dry out.
Lamb’s ears,
Stachys byzantina
12–18 June P FS, SS WD S, L M Will grow in dry, poor soils. Woolly grayish leaves.
Lady’s mantle,
Alchemilla mollis
10–12 June–July Y FS, SS M L M Compact, spreading habit. Prefers a cool, moist location.
Lavender,
Lavendula angustifolia
12–20 July–Aug. L FS WD S M Likes poor soil. Very fragrant foliage.
Leadwort,
Ceratostigma plumbaginoides
8–12 Aug.–frost B FS WD S E Sometimes called plumbago. Semiwoody groundcover.
Lenten rose,
Helleborus niger
5–8 Feb.–March W SS M, WD L C Needs rich soil. Do not transplant or cultivate.
Leopard’s bane,
Doronicum caucasicum
12–18 April Y FS, SS M, WD L E Dormant in July–Aug. Plant among spring bulbs.
Liatris, Gayfeather,
Liatris sp.
24–48 July–Sept. W, L FS WD S E Adapts well to dry locations. Spike flowers open from top downward.
Lily turf,
Liriope muscari
6–10 Aug. V, W FS, SS, S WD S, L E Evergreen border plant or groundcover. Cut back old growth in spring.
Lily-of-the-valley,
Convallaria majalis
6–8 May W, P SS M, WD L E Used for groundcover and cutting of flowers.
Loosestrife, yellow,
Lysimachia punctata
18–30 July–Sept. Y FS, SS M, W L E Needs semishade in dry soils.
Lungwort,
Pulmonaria longifolia
8–12 May–June B SS, S M L M Very distinctive foliage with unusual variegation.
Lupine,
Lupinus hybrids
24–40 June–July B, W, P, Y FS, SS WD S C Dislike hot summers. Short-lived in Midwest.
Meadow rue,
Thalictrum aquilegifolium
24–30 June–July P, V, W FS, SS M, WD L M Foliage like columbine. Male and female plants.
Meadow sweet,
Filipendula vulgaris
24–36 June–July W, P FS, SS WD L E Fleecy, graceful flowers. Prefers humusenriched soil.
Painted daisy, Pyrethrum,
Tanacetum coccineum
12–24 June–July P, R, W FS WD L C Will not tolerate wet soils. Replant every 3 years.
Pasque flower,
Pulsatilla vulgaris
6–10 April B, W FS WD S M For rock garden. Needs good drainage. No acid soil.
Peony,
Paeonia hybrids
18–36 May–June W, P, R FS, SS WD L E Transplant in Sept. Plant 2 to 3 inches deep in rich soil.
Perennial salvia,
Salvia x superba
18–24 June–July B, V FS WD L E Effective blue flower color.
Phlox, Creeping,
Phlox subulata
3–5 April–May P, L, W FS WD S M Also called ground pink or thrift. Tolerates poor soil.
Phlox, Garden,
Phlox paniculata
18–48 June–Sept. R, P, L, W FS, SS WD L M Many varieties available. Sometimes listed as P. decussata.
Pincushion flower,
Scabiosa caucasica
18–24 June–July B FS WD L M Unique flower with conspicuous stamens.
Pink, Cottage,
Dianthus plumarius
10–15 May–July R, W, P FS WD L M Very fragrant. Bluish gray foliage. Edging plant.
Pink, Maiden,
Dianthus deltoides
4–9 May R, P, W FS WD S M Dwarf pink. Gradually spreads to form a green mat.
Poppy, Iceland,
Papaver nudicaule
8–12 June R, O, P, W FS, SS WD S M Often grown as annual. Seeds started indoors will flower in first season.
Poppy, Oriental,
Papaver orientalis
24–40 May–July O, R, P, W FS WD S E Needs good drainage. Place in protected spot, or mulch in winter.
Primula, Primrose,
Primula polyantha
8–12 May B, O, Y, R SS WD S M Must be kept moist. Cannot survive summer heat and drought.
Red-hot poker, Tritoma,
Kniphofia hybrids
36–48 July–Sept. O, Y, P, W FS WD S E Needs excellent drainage. Mulch in winter.
Rock soapwort,
Saponaria ocymoides
5–10 June–July P, W FS WD S M Pruning back helps retain compact form. Needs good drainage.
Russian sage,
Perovskia atriplicifolia
36–48 June–July B FS WD L E Uniquely colored, aromatic foliage. Good companion for plants with yellow flowers.
Sea lavender,
Limonium latifolium
15–24 Aug.–Sept. B, W FS WD S M Sometimes called statice. Large decorative foliage.
Sedum, Stonecrop,
Sedum sp.
4–24 June–frost P, R, Y, W FS WD S E Many species available with differing growth habit and flower color.
Shasta daisy,
Leucanthemum x superbum
12–36 June–Aug. W FS WD L M Needs replanting every 2 to 3 years. Dwarf and tall forms available.
Snow-in-summer,
Cerastium tomentosum
3–5 May–June W FS WD S M Small gray woolly leaves. Forms dense carpet. Needs excellent drainage.
Spiderwort,
Tradescantia virginiana
8–24 May–Aug. B, V, W SS, S M, WD L E Easily grown. Roots easily from the nodes.
Stoke’s aster,
Stokesia laevis
12–30 Aug.–Sept. B, W, P FS WD S M Needs good drainage. Mulch in winter.
Sweet pea, Perennial,
Lathyrus latifolius
60–96 June–Aug. P, R, W FS, SS M, WD, D L E Very easy to grow. May crowd out other plants.
Sweet William,
Dianthus barbatus
6–15 May–June R, P, W FS WD S E Biennial that self-sows easily. An “old-fashioned” favorite.
Thrift,
Armeria maritima
8–12 June–July P, V, W FS WD S E Needs good drainage. Mulch in winter. An everlasting.
Tickseed,
Coreopsis grandiflora
24–36 June–July Y, O FS WD L E Tolerant of dry soils. Good for low maintenance areas.
Veronica, Speedwell,
Veronica sp.
2–36 May–Sept. B, W FS WD L E Easy to grow. Species differ in growth habit.
Violet,
Viola sp.
6–8 April–May V, L, W, Y FS, SS WD, M L E Forms a dense mat. Reseeds easily.
Yarrow, Sneezewort,
Achillea sp.
2–36 June–Aug. Y, P, R, W FS WD L E Easy to grow, but should be replanted every 3 to 4 years.