Move over, ferns and hostas…there’s nothing quite like astilbes, or false goat’s beard, to bring flair and panache to the shadier nooks in our gardens. Their elegant plumes contribute rich color and height from late spring into early summer, and again in late summer. Even when out of bloom, the attractive foliage stays neat and tidy before gradually going dormant.
Astilbes are a dream to work with. Excellent understory plants, they work under deciduous trees and among a wide range of shade-loving species. This useful perennial is a “must-have” for any location that’s not in strong sun. They do well in heavy clay, too, a bonus here in eastern Pennsylvania.
Astilbes make up some 18 herbaceous species in the saxifrage family, most of which are native to Asia and a few to North America. Numerous hybrids make up several groups or strains with common characteristics. All prefer moist, slightly acidic soil and some shade.
Sporting densely packed panicles on strong stems, the blooms sit atop deeply-cut, fern-like foliage. Colors range from a creamy white to every shade of pink and purple, even a few reds. Hybrids are notable for their diverse panicle forms — spidery, conical, starfish-shaped. The deeply-cut foliage emerges bronze or deep green on short wiry stems from rhizomes. By planting cultivars with different bloom periods you can enjoy astibles for twice as long.
Early or Late?
Early blooming hybrids are the most well-known, and are found in the arendsii and japonica groups. They flower in May and June. Later-blooming varieties are usually of chinensis and simplicifolia parentage and bloom in August. But this is not a hard and fast rule. It’s best to ask at the nursery or check the tag before buying.
All have inflorescences composed of many tiny florets packed together into panicles, which gradually turn caramel and brown from the bottom up as they die and ripen into seedheads. Astilbes are neither fragrant nor particularly attractive to pollinators.
After bloom, the dried seedheads can be left in place for architectural interest, or deadheaded for a neater look. They reach heights from 8 inches for dwarf varieties to nearly five feet, with most falling in the 18- to 24-inch range. The foliage is somewhat shorter.
Popular early to mid-season bloomers are:
- White: Europa; Deutschland; Bridal Veil
- Apricot Pink: Younique Salmon; Peach Blossom; Delft Lace
- Rich Pink: Rhineland; Ostrich Plume
- Magenta-Purple: Visions/ Vision in Purple; Stand and Deliver
- Red: Fanal; Montgomery; Red Sentinel
Late bloomers to consider:
- Palest Pink: Milk and Honey
- Magenta Pink: Vision in Pink; Dwarf Pumila (8″); Maggie Daley
- Purple: Purple Candles; Purpurlanz; Superba (5 ft)
- Red – August Light
Of course, there are new varieties coming out all the time, so feel free to choose something else. You really can’t go wrong.
Using Astilbes in the Landscape
Astilbe foliage makes a lush summer groundcover, but they should be sited among other plants because the early-blooming varieties go dormant before summer’s end. They look best with ferns, hostas, heuchera, tiarella, jacobs ladder, brunnera, even pachysandra, as long as the latter isn’t allowed to overrun them. Spring phlox, bulbs, dame’s rocket, foxglove, woodruff, columbine, epimedia, bugbane and goatsbeard all make good astilbe companions.
Out of bloom, flowering shade annuals such as begonias will keep the color going. I like to keep warm red cultivars like Fanal separate from the cooler pink and purple astilbes, pairing them instead with white, pistachio or burgundy companions. The varied textures and colors of bugbane, aralia, hosta, and ferns will enliven any astilbe bed.
Growing Astilbes
Astilbes love moisture, so make sure you put them where they won’t dry out quickly. They will need water during dry spells. Some cultivars claim to be more drought tolerant than others, but they all benefit from plenty of moisture. Otherwise they will quickly go dormant and lose vigor. They like rich organic matter that’s slightly acidic, so amendments of compost or leaf mold is always a good idea. Woodland soil is perfect. A bit of Holly-tone will help with acidity.
While astilbes will grow lush foliage in full shade, you won’t get much flowering without 2 hours or more of morning sun. Avoid strong afternoon sun or anywhere there’s going to be reflected heat, such as against a sunny foundation wall. Dappled shade is great if you have it.
Happy plants will slowly spread outward from the rhizomes over time. Large clumps can be divided every 3 to 4 years. Division will help invigorate them as well as multiply your collection. Dig up and separate them into two or three sections in early fall, allowing enough time for the new plantings to establish before winter. Mulch well and keep watered until they go dormant.
Siting
Whether you are dividing older clumps or planting anew, group several plants of the same color together, about a foot apart. You can then group the masses into drifts for even more impact. By varying the panicle forms and planting in bands of complimentary shades, you can achieve an impressive display. The photo below shows a cleverly layered effect, with taller cultivars to the back and shorter in front. The lacey pale pink in front looks like Delft Lace, a particularly pretty cultivar. Notice how the bands alternate dark and light colors.
Astilbes love phosphorus to bloom well, so fertilize them in spring with a slow-release, granular fertilizer and optionally in late fall to avoid stimulating top growth. Some gardeners leave the seedheads on over winter for added interest. However, I cut mine back to within 2 inches of the ground each fall, and remove the foliage for a tidier look and less chance of rot in our wet winters.
The tallest varieties look best with something planted in front of them, as the bottom half of the stems can be sparse. Lower plants in front will also help disguise the browning panicles as they fade. They will reward you with color that just keeps going, right into fall!
For that boring damp spot you haven’t done much with up until now, it’s time to add some sparkle. Astilbes are a great place to start.
