ASTILBE: False Spirea
Astilbe have been cultivated since the late 1700s and since have become a staple in the shade garden. They offer a feathery texture with the foliage and great vertical, fluffy spires of flowers. Blooms in June, July, or August come in shades of pink, lavender, red, and white and are wonderful as cut flowers when many blooms of the shade garden have past.
Besides their lovely appearance, Astilbe are one of the best choices for the ever–so–common semi–shady moist spot in the garden. With that in mind, they combine well with hosta, Acorus, Ligularia, ferns, Pulmonaria, and Japanese iris. Since they have been admired for centuries there is an overwhelming array of varieties and hybrids available. Here we have broken down the varieties into the major groups, which share characteristics such as bloom time density, and vigor.
Astilbe x arendsii
Hybrids from Germany bloom in mid to early season with perhaps the widest bloom color selection and dark new leaves. They are hardy in zones 5–8.
Some varieties include:
- 'Amethyst' – Early, lilac pink flowers, plants reach 30–36" tall and 24" wide.
- 'Bridal Veil' – Profuse, white to creamy yellow flowers. Plants reach 30" tall and
- 'Fanal' – Early, dense, crimson red flowers and bronze new growth. Award
wining variety. 24" tall and 18" wide.
- 'Hyacinth' – Early to mid dark lavender pink blooms. Larger plants reaching 36"
tall and 18" wide.
Chinese astilbe are exceptionally vigorous in growth and have dense, later blooming (July – August) flowers. They are hardy in zones 5 – 8.
Some varieties include:
- 'Pumila' – A distinct variety for it's dwarf habit, 8 – 10" tall and 10" wide. Dense mauve to lilac plumes. Great edging plant.
- 'Vision' Series – a group of midsize Astilbe reaching 12 – 18"tall and 20" wide. Lacy foliage is topped by dense flowers in shades or pink, red, or white.
Astilbe x japonica
Japanese hybrids are early to mid season (May, June, or July) bloomers with wide fluffy spires.
- 'Montgomery' – A dark red flowering variety with glossy green leaves that emerge bronze in spring. It grows 20" tall and wide.
- 'Peach Blossom' – Pale pink to peach flowers in May and June. Grows 24" tall and 18" wide.
- 'Rhineland' – Dense, bright pink plumes in May through June. Plants reach 2' tall and wide. Described as one of the best early blooming varieties.
This group of Astilbe is smaller with finely cut foliage, and shorter light pink blooms. The most readily available variety is 'Sprite'. It has light pink plumes in June and grows 10 – 12" tall and wide.
This group has dramatic, large, drooping panicles in July and August. The plants are also larger growing and cold hardy to zone 4. 'Straussenfeder' (a.k.a Ostrich Plume) has graceful, arching magenta plumes on plants that reach 30" tall and 20" wide.
Common Name: False Spiraea
Origin: The genus Astilbe consists of approximately 12 species from east Asia and North America.
Culture: Astilbe are hardy, deciduous perennials that thrive in partial or dappled shade and moist soils. They can grow in well–drained soils with regular water and along the moist edge of a pond. It is essential Astilbe do not dry out in summer.
Maintenance: Astilbe require little maintenance other than division of old plants when the center of the clump dies out (about every three years). Encourage maximum blooms with yearly fertilizing with compost and/or a granular all–purpose fertilizer.
Pest and Disease: As with other members of the Saxifrage family, Astilbes are susceptible to root weevil. They can be controlled with beneficial nematodes in the spring.