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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Astilbes

This article was published originally on 7/14/2000

While hostas are terrific plants for shady locations, a number of other perennials are wonderful additions to the shade garden. One of the best perennials for shade is astilbe, or false spirea. Astilbes have beautiful spike-like clusters of flowers that sway gracefully in the wind. Flower colors include white, pink, red, and reddish purple. The flowers are borne on stiff, upright or arching stems. Astilbe foliage varies from dark green to bronze. The astilbe's combination of colorful flowers and attractive foliage make it a perfect complement to the bold coarseness of hostas. Astilbes also make wonderful cut or dried flowers. Allow a few spent flower blossoms to remain on the plants in fall and you will be rewarded with elegant brown spikes through much of the winter.

Astilbes shine when many other shade loving perennials are waning. They bloom for 2 to 3 weeks. Depending on the variety, astilbes flower from early to late summer. Early blooming varieties begin to flower in late May or June while late bloomers begin in late July or early August. By selecting several varieties with different bloom times, the floral display can be extended over 2 or 3 months.

Astilbes also vary greatly in height. Some varieties like 'Sprite' or 'Perkeo' grow only 6 to 12 inches tall (bloom included), while 'Purple Lance' or 'Purple Candles' can reach 4 feet in height. This diversity in height makes astilbes versatile perennials well suited to many areas of the perennial border.

Fertile, moist, humus-rich soil is a must for these shade lovers. Astilbes are unforgiving in dry soils, as the leaves will brown quickly. Annual additions of compost or organic matter around the base of the plant will be rewarded with loads of blooms and healthy foliage. While astilbes require consistent moisture, they do not tolerate waterlogged or heavy clay soils well. Clay and poorly drained soils can be improved by incorporating peat moss, compost, or other types of organic matter into the soil before planting.

Astilbes are easily propagated by dividing large clumps when the foliage emerges in early spring. Vigorously growing astilbes can be divided every 4 to 6 years After division, water and mulch well to aid establishment.

Astibles are native to China, Japan, and Korea. There are 25 different species. Hundreds of hybrids or selections have been made from approximately a dozen species. 'Peach Blossom', the first cultivar introduced in 1903, is still available on the market today.

Please see the following chart for a listing of a few of the cultivars that are available with height, flower color, and bloom time for each.

Cultivar Height (in.) Flower Color Bloom Time Comments
A. x arendsii types
America 28 Lilac rose Early - Mid
Bressingham Beauty 36-40 Pink Mid Arching plumes
Bridal Veil 18-24 White Mid
Bumalda 24 Pinkish white Early - Mid
Catherine Deneuve 24-30 Rose-pink Mid
Cattleya 36-40 Orchid-pink Mid - Late Long blooming
Erica 30-36 Pink Early - Mid Compact trusses
Etna 24-28 Dark red Mid Dark foliage
Fanal 24 Red Early - Mid Bronze foliage
Granat 24-28 Carmine red Early - Mid Bronze foliage
Rheinland 24 Carmine rose Early - Mid
Snowdrift 24 White Early - Mid
White Gloria 20-24 White Mid Blocky plumes
A. chinensis types
Pumila 10-12 Lavender pink Late Groundcover type
Purple Candles 36-42 Reddish purple Late Compact trusses
Veronica Klose 20-24 Purple rose Late
Visions 12-18 Lilac purple Late Compact trusses; bronze foliage
A. crispa type
Perkeo 6-10 Rose Late Crisp foliage; zone 5 hardy
A. x japonica types
Cotton Candy 12-16 Pink Mid - Late Compact foliage
Deutschland 20-28 White Early Fragrant flowers
Elisabeth 24-28 Raspberry lilac Mid Purplish foliage
Montgomery 24-36 Dark red Mid Dark foliage
Red Sentinel 24-36 Scarlet red Mid - Late Dark foliage
A. x rosea type
Peach Blossom 20-30 Peachy pink Early Fragrant flowers
A. simplicifolia types
Aphrodite 15-20 Salmon red Late Bronze foliage
Hennie Graafland 16-18 Light pink Late Shiny dark green foliage; arching plumes
Sprite 6-12 Shell pink Late Dark bronze foliage
A. x taquetii types
Superba 36-40 Rose purple Late
Purple Lance 42-46 Pinkish purple Late
A. x thunbergii types
Ostrich Plume 36-40 Salmon pink Mid Arching plumes
Prof. van der Wielen 36-40 White Mid Arching plumes



This article originally appeared in the July 14, 2000 issue, pp. 88-89.

Year of Publication: 
2000
Issue: 
IC-483(17) -- July 14, 2000