Those of us with more shade than sun often bemoan the lack of color in our gardens. We might try to talk ourselves into believing that shades of green count as color diversity, but our hearts know better. Gardens can't live by hostas alone.
One of the most colorful perennials for shade, Astilbe, is a way into other parts of the color wheel. The blooms can range from white to cream through the pinks, to reds and dark purples. Soft, fuzzy flowers on upright stems provide great contrast to the more rounded and spreading forms of shade plants such as wild ginger, hydrangea, Brunnera, Pulmonaria and, of course, hosta. They also look great with ferns.
Astilbe's common name, false spirea, is not actually all that common; generally they are simply called by their Latin name. There are about 18 species of astilbe, and many hybrids. Plants are native to China, Japan, and Korea, with one in North America.
It doesn't hurt that astilbe foliage, deep green and finely cut, is interesting in its own right, and is an attractive counterpoint to the foliage of other shade-lovers. Varieties range in height from dwarf plants to those four feet tall.
There are astilbe varieties that bloom in early- mid- and late summer. By choosing the right varieties, it's possible to have plants in bloom much of the summer. They are dramatic in groups of three, five or seven. As singles they can look lonely.
Astilbes should be a mainstay of every shade garden. They tolerate heavy shade and black walnut trees, and deer and rabbits don't eat them. Plant them anywhere you need color in the shade: woodland gardens, as foundation plants, as a groundcover, or near water. They can even be grown in containers, though they need large ones, at least 16" wide and deep.
How to Grow
Location: Astilbe is hardy in USDA Plant Hardiness Zones 3 to 9. Allow 18 to 24" spacing between plants.
Soil: Should be moist, well-drained, and rich in organic matter. The pH can be neutral to slightly acidic. Mulching after planting helps conserve moisture. Will tolerate clay soil.
Light: Part to full shade. Even in part shade, avoid hot afternoon sun, if possible. Don't plant in full sun. In deep shade flowering may be reduced.
Water: Medium water requirements. Keep the soil moist, but not wet. The soil should not dry out. In prolonged hot weather or if the soil gets too dry the leaves will brown and crisp. In the hotter West and South, astilbe needs deeper shade and more water.
Feed: Add compost when planting if desired. Fertilize once a year in spring by incorporating a granular fertilizer high in phosphorous into the soil. Or use seaweed or fish emulsion.
Care: Astilbes are low maintenance, with few pest or disease problems. Japanese beetles may eat the leaves. Deadheading won't produce more blooms so either deadhead or keep the dried flowers on the plants for fall and winter interest. Divide astilbes in early spring every three to five years.
'Chocolate Shogun' has chocolate-maroon leaves and blush pinkish-white flowers. Grows to about 2' and blooms in midsummer. It is said to be able to handle more sun than most astilbes, but only with adequate moisture.
'Deutschland' is an old variety, readily available, with white flowers on a plant that grows 1 ½ to 2 feet tall. It blooms in mid- to late spring.
'Fanal' has crimson-red flowers. Emerging foliage is bronze changing to green. It grows from 1' to 1 ½' tall. Blooms in midsummer.
'Ostrich Plume' has weeping, bright pink flowers that sway in the breeze. Grows about 2 ½' tall. Blooms early summer.
'Purple Candles' has flowers that are less plume-like and more upright. Blooms later in summer after most other astilbes are finished. One of the tallest, it can grow to an eye-catching 3 to 4'.
Astilbe is touted as a great cut flower if cut when the flowers are half open. However it seems a shame to take them from the shade garden, where their bright colors add so much.
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