American gardeners are in the midst of a passionate love affair with Astilbes. Native to the far east, these beautiful plants and their hybrids have revolutionized the perennial possibilites of moist, shaded American gardens. Astilbes are companions of ferns and impatiens--they're some of the few flowers that make big color in full or partial shade.
The vast majority of the scores of hybrids now available are the work of one man, master hybridizer Georg Arends (Yes, that's why you keep seeing "arendsii" tacked onto hybrid names.) Mr. Arends, working in Ronsdorf, Germany spent decades hybridizing sedums, phlox, campanulas... and his first love, astilbes.
In 1933 alone, Arends introduced 74 different astilbe cultivars, and there have been hundreds since. It took awhile for them to become popular in the US, but these days, they're more popular every year.
These plume-flowered plants have ultra-handsome fern-like foliage, (usually dark glossy green) and stiff stems that always hold the elegant plumes aloft without any staking. Flower arrangers find the flower plumes are just as handsome in a vase as in a garden.
Watch Our All About Astilbe Video
From tiny dwarfs to big draping hybrids, astilbes are all quite easy to grow, as long as their ground is not in the blazing sun and does not dry out for long. They must have plenty of moisture, so choose your locations carefully. If the soil is not loamy, add some peat moss or other moisture-retaining material. You'll know after one growing season whether your plants are happy where you've put them. If not, think about moving them to a better spot before they weaken.
With these plants, mulching is important, especially if they are planted where they will get some direct sun. Bark chips or any other good moisture-retaining top mulch will be very helpful in maintaining the constantly-moist ground they prefer.
They need no more than the usual feeding, like most flowering perennials. For feeding perennial gardens, my favorite perennial expert, Frederick McGourty, recommends familiarizing yourself with standard perennial flower fertilizers, which are always labeled with three numbers in a sequence, such as 5-10-5 or 5-10-10, or 10-10-10. These numbers on the bag refer to percentages of Nitrogen, Phosphorus and Potassium, in that order. McGourty explains that the most important element here for flowering plants is the middle number, Phosphorus, so he recommends choosing a fertilizer with the middle number no lower than the other two.
If your garden is new, try to rake in your fertilizer a week or two before planting. And in later years, one feeding in spring (remove the mulch, and rake it in) should do. If you use dry granular fertilizer, remember to scatter it when the soil is wet and the foliage of your plants is dry. Dry fertilizer sticking to stems and leaves can burn the plants.
If you're new to the neighborhood, it's always good to give your local county extension agent a call, and discuss soils and feeding with him or her. That's what they're there for. It's great local advice, and it's free. You'll find the number in the phone book under US Government, Cooperative Extension Services.
In the right locations, astilbes grow vigorously. In fact, after a year or two, you'll have big clumps you'll want to divide. And that's easy too. The best time is just after flowering. Water deeply, and then just dig up the clumps and pull the roots into pieces. Try to keep the pieces large, so each one will quickly become a full size plant. Of course, get them back into the ground as soon as possible.
Garden Design with Astilbes
One of the beauties of this perennial group is that you can use them in either informal ways for casual fountains of color as you see in the big photo at the top of this page, or you can also use them in a more formal way. I once divided about 5 big clumps into about 30 plants, and planted 15 on each side of a short pathway. The next spring, the path was elegantly lined with perfectly matching plants, all with identical plumes in height and color. After bloom, the walk was edged with neat handsome hedges of their foliage. Garden designers also know that many astilbes put on a second show with changes in fall foliage color, too.
A fine choice for moist shady soil, particularly when used as a groundcover, ‘Pumila’ Astilbe will light up your garden in late summer with slender, feathery plumes of lavender pink. The finely dissected, fern-like foliage of this Chinese dwarf variety is low growing and spreads rapidly via rhizomes. Blooms later than other astilbes. (Astilbe chinensis var. pumila)
'Sister Theresa' Astilbe glows with thick, cotton candy-colored plumes that sway softly in the breeze. Mounds of finely-cut, green foliage remain true throughout the season, providing a graceful backdrop for later-blooming flowers. Lovely in rock gardens and when planted in drifts. Prefers moist soil. (Astilbe arendsii)
A departure from the more familiar upright astilbes, 'Straussenfeder' creates a fountain of rich pink, weeping blooms that bend and arch with grace. Flowering in mid summer, this variety still prefers a shady spot and moist soil. 'Straussenfeder' Astilbe is sometimes called Ostrich Plume, because of its dramatic draping plumes. (Astilbe thunbergii)
A striking giant for the shade garden, 'Purpurkerze' Astilbe grows up to 42 inches tall with spectacular, candelabra-like flowers in rich purple. Foliage is deeply-cut and carries a bronze tint. Like other astilbes, 'Purpurkerze' prefers shade and moist soils, but seems to have more tolerance for drought and sun. (Astilbe chinensis)
Looking to add bold, bright color to a shady spot in your garden? Our Astilbe Mix is an amazing choice, providing a variety of color to the mid-summer garden with unique, spiky flower plumes that don’t require staking. Also known as False Spirea, our Astilbe Mixture is deer resistant and amazingly easy to grow. Make sure to plant extra, as these blooms make for gorgeous summer bouquets and last all year long if dried. Astilbe makes a bold statement on their own or paired with other shade-loving perennials, such as Hostas and Columbines.
'Deutschland' Astilbe's pure white plumes are lovely in the moonlight and can brighten the shade garden with grace. Soft and feathery flowerheads play beautifully against the glossy green, mounding foliage. Very showy and very easy to care for, like most astilbes, this one is resistant to both deer and rabbits. Try pairing with any fern for a gorgeous, contrasting look. (Astilbe japonica)
'Montgomery' Astilbe produces feathery, magenta-crimson blooms that stand tall over its deep green foliage. A standout addition to the shade garden, 'Montgomery' delivers loads of color and is a perfect choice for mass plantings. Leaves emerge bronze-red in spring and turn green over the course of the season. Prefers moist soil. (Astilbe japonica)