Astilbe or False Spirea

(Saxifragaceae - Saxifrage Family)

Form

• usually a small herbaceous perennial, although some forms are medium-sized
• ranging from 1' to 5' tall by 1' to 2' wide, depending upon species, hybrid, and/or cultivar; most are about 1.5' tall by 1' wide
• upright clump growth habit

Culture

• partial shade to full shade
• performs best in evenly moist, rich, organic, well-drained soils in partial shade, but is somewhat tolerant of more harsh conditions as long as sufficient moisture is provided during the dry periods of Summer
• propagated primarily by crown division, but also by seeds or tissue culture
• Saxifrage Family, with no significant disease or pest problems
• abundantly available in containers, with many species, hybrids, and cultivars
• remove debris from the previous year's growth in early Spring, before new growth emerges
• wilting and dieback of the attractive foliage for the remainder of the season during hot, dry Summers can be avoided by regular Summer irrigation

Foliage

• ternately or biternately compound leaves with leaflets that are ovate and doubly serrated, emerging from the crown as red, bronzed, or green foliage and usually maturing as bronzed, dark green, or medium green foliage that is dull shiny, depending upon the species, hybrid, and/or cultivar
• fall color is unchanged if the foliage has persisted into Autumn, as the plant sometimes dies back to the crown and enters a season-ending dormancy during hot, dry Summers

Flowers

• inflorescences are solid-colored, pyramidal, fine-textured, and arising from the center of the crown, with one to many plumes per plant
• colors include white, cream, pink, lavender, violet, purple, red, or scarlet
• often a prolonged (two to six week) bloom period during the months from June to September, depending upon the species, hybrid, or cultivar

Fruits

• fruiting stalks sometimes provide an ornamental Winter effect against a snowy background, and may either be left as is, or deadheaded to enhance the foliage effect in Summer

Twigs

• not applicable

Trunk

• not applicable

ID Summary

• ternately or biternately compound leaves form a dense basal clump of foliage, with flowering stalks rising from the center of the clump and yielding fine-textured, pyramidal inflorescences in a wide array of solid colors
• flower height ranges from 1' to 5', the bloom period occurs in June, July, or early September, and the foliage may be bronzed to green and is often dull shiny, all depending upon the variant that is chosen

USAGE

Function

• entranceway, foundation, bed, edging, border, or raised planter shade perennial, often used effectively in group or mass plantings
• nearly continuous bloom of Astilbes can be accomplished throughout the Summer growing season by placement of various types throughout the perennial garden that have sequential bloom periods (see the list below for some of the more popular examples)

Texture

• fine texture in foliage and when flowering
• open to average density

Assets

• feathery plumes of fine-textured, solid-colored inflorescences above the foliage
• shade-loving perennial

Liabilities

• most modern hybrids are not especially heat or drought tolerant, and will exhibit wilting and foliage dieback due to mid-Summer dormancy unless supplemental irrigation is applied

SELECTIONS

Alternates

• fine-textured floral display of perennials (Aruncus, Eremurus, Ligularia 'The Rocket', Miscanthus sinensis, Pennisetum, etc.) or annuals (Ageratum houstonianum, Celosia [plumosa type], Lobularia maritima, etc.)

Habitat

• zones 4 to 9
• native to the Orient

Variants

• various species, hybrids, and cultivars are noted for different bloom periods, height, floral color, foliage color, and glossy or dull foliage
• Astilbe x arendsii 'Fanal' - an early blooming (early to mid June) cultivar with dark red inflorescences, to 2' tall; a popular cultivar for over 60 years, one of the first introduced by George Arends, for whom the hybrids were scientifically named
• Astilbe chinensis 'Pumila' - a late blooming (August to September) lavender pink dwarf form (up to 1' tall) with tomentose foliage, slowly spreading underground by rhizomes, effective as an edging groundcover for shady sites, and moderately drought tolerant
• Astilbe x japonica 'Deutschland' - an early blooming (early to mid June) cultivar with white inflorescences, to 2' tall
• Astilbe simplicifolia 'Sprite' - a midseason (late June and July) pale pink blooming form with glossy basal foliage that emerges bronzed, up to 1.5' tall
• Astilbe taquetti 'Purple Candles' - a midseason (late June and July) purple blooming form with bronzed basal foliage, up to 4' tall, drought tolerant, and with the capacity to rebloom if deadheaded and watered

NOTES

Translation

• Astilbe translates as "without brilliancy", referring to the individual flowers that are tiny; the name of the genus was assigned long before modern cultivars were bred and introduced that have large, showy inflorescences (made up of hundreds of individual small flowers) as compared to the species forms.

Purpose

• Astilbe is a perennial for the shade, noted for its fine-textured pyramidal inflorescences, good foliage, and Winter fruiting-head effect.

Summary

• Astilbe is a Summer-flowering, shade-loving perennial having terminal plumes of feathery inflorescences held above the basal compound foliage, effectively used in group or mass plantings.