Astilbe x arendsii
Valued for light, airy quality of plumelike flower clusters and attractive foliage and for ability to provide color from late spring through summer. Leaves are typically divided, with toothed or cut leaflets, though in some species they are simply lobed, with cut margins. Small white, pink, or red flowers are carried in graceful, branching, feathery plumes held on slender, wiry stems ranging from 6 in. to 3 ft. or taller. Most plants grow 2–3 ft.wide.
Astilbes are the mainstay of the shady perennial border, although in cool-summer climates they can withstand full sun if watered adequately. Effective at the edge of pools, along shady paths, in containers. Need moist (but not boggy), rich soil with ample humus. Cut off faded flowering stems and divide clumps every 4 or 5 years. Survival in coldest areas (Zones 1a, 1b, 2a) depends on good snow cover.
Most astilbes sold belong to this hybrid group or are sold as such. Parentage is complex, but plants often have A. japonica, A. chinensis, and/or A. thunbergii in their ancestry. The plants differ chiefly in technical details. All can take full sun only in cooler climates. Short-lived in Zones 8, 9, 18–24. The following are some of the best varieties.
‘Bridal Veil’: Midseason to late. Full white plumes to 3 ft. tall.
‘Color Flash Lime’: Midseason. Pink flowers rise about 2 ft. above light green foliage that picks up bright yellow tones.
‘Color Flash’: Midseason. Pink flowers rise about 2 ft. above colorful foliage. Leaves gradually turn from green to burgundy.
‘Deutschland’: Early. White flowers to 1 1/2 ft. tall. Bright green leaves.
‘Fanal’: Early. Bronzy foliage is topped by blood-red flowers 1 1/2–2 1/2 ft. tall.
‘Rheinland’: Early. Deep pink flowers 2–2 1/2 ft. tall.
This strain grows to 20 in. tall and wide, with variegated foliage and blue, red, pink, purple, or whi...
Low mats of leaves are topped by lilac-pink flower clusters that rise to 12–15 in. high.
Blooms in late summer, grows taller than A. x arendsii, and tolerates dryness a litt...