HARDINESS: Zones 3 to 8
PREFERRED SOIL pH: Slightly acidic
PREFERRED SOIL TYPE: Moist, fertile, organic
PREFERRED LIGHT:Partial shade
ATTRIBUTES: White, pink, purple, or red plumelike flowers; ferny foliage; for beds
SEASON OF INTEREST: Summer
FAVORITES: Red 'Fanal', purple 'Hyacinth', pink 'Sprits', white 'Bridal Veil'
QUIRKS: Needs consistently moist soil
GOOD NEIGHBORS: Bee balm, ferns, hostas, iris, lady's mantle
WHERE IT GROWS BEST: In light shade and moist soil
POTENTIAL PROBLEMS: Slugs and snails, Japanese beetles
RENEWING PLANTS: Lives many years; dig and divide every 3-4 years, in spring or fall
CRITTER RESISTANCE: Good
SOURCE: Nursery plants, division
DIMENSIONS: 1-4 ft (0.3-1.2 m) tall, 2-4 ft (0.6-1.2 m) wide
Astilbe in the Landscape
Plush plumes of color wave above the fernlike foliage of these splendid and extremely cold-hardy perennials. Astilbes are truly majestic when topped by a profusion of white, pink, salmon, lilac.or red feathery blossoms that linger for weeks in summer.
Astilbes are not strictly for shade, although they are often grown there. Where summers are not oppressively hot, you can grow this plant in full sun. Astilbes are ideal for brightening patches under tall trees or walls and fences. A swath of astilbes turns a damp, hard-to-plant area into a showpiece. In shady settings, plant astilbes with hostas. Given a little more sun, astilbes make pretty companions for bee balm, lady's mantle, and irises. Astilbes look gorgeous in containers with ornamental sweet potato vines, dahlias, and licorice plants.
A Carnival of Color
Astilbes offer a broad range of flower colors, and bloom times vary, so you can combine them for an extended period of color. 'Sprite' is a charming pink-flowered miniature, perfect for edging or pots, and hardy enough to overwinter in outdoor pots. The widely available Astilbe x orendsii cultivars bloom in June and July and range from the deep red-flowered 'Fanal' and dark pink 'Gloria Purpurea' to purple 'Hyacinth' and frothy white 'Bridal Veil'. A. chinensis cultivars, such as mauve-flowered 'Finale' and rich rose 'Serenade', usually bloom in August, as do the tall and stately 'Superba' and other A. tacquetii cultivars. Very late-blooming A. chinensis 'Purple Candles' begins in August and continues into September.
Astilbes are no-nonsense, trouble-free plants that will survive for years. The optimal growing site has consistently moist, fertile soil. Dig in a 2-3 in (5.1-7.6 cm) thick layer of organic matter at planting time, and cover the soil around plants with a 2 in (5.1 cm) layer of moisture-retaining compost or leaf mold. To increase flowering in subsequent years, fertilize in spring with an organic or controlled - release fertilizer. After 3 to S years the plants may become crowded. Rejuvenate by lifting the plants and using a knife or sharp shovel to divide the woody bases before replanting.
Astilbes wilt and brown quickly if not watered during drought. They can go dormant and may eventually perish. The first symptom of dissatisfaction is leaf tip browning, but new growth will sprout if supplemental water is forthcoming. When you water, soak the soil deeply, allowing it to dry between waterings. Other than root rot, which occurs when the soil is constantly soggy, astilbes resist disease. Although the plants are virtually pest free, raggedly chewed leaves can reveal the work of night-feeding slugs and snails. Set saucers of beer on the soil to lure and drown these pests. In the eastern part of the country, Japanese beedtles may chew leaves of plants growing in full sun. Spray with the botanical insecticide neem.To avoid future problems with sun-loving beetles, plant in partial shade.