Gardening 101: Astilbe

Astilbe, Astilbe x arendsii: “False Spirea”

Astilbe is a perennial plant that the noted American garden writer Allen Lacy praised as “vertical pizzazz.” Not only is it gorgeous but also it’s easy to grow.

I learned this firsthand in the early 1990s. After spending several years gardening in a Manhattan apartment house on a sunny but acrophobia-inducing terrace so narrow it would be more accurately referred to as a ledge, I acquired an actual plot of land. It was located behind a tiny 1920s house that my husband and I purchased in Queens, New York. How thrilled I was to claim my very own acreage. I set about acquiring plants I knew how to grow and which had thrived with aggressive enthusiasm on my sunny terrace: tomatoes, basil, peppers, zinnias, lavender, etc. All classic sun lovers.

I planted them and then I waited. The first hint that things were not going to go well was when the next-door neighbor expressed great surprise that I was planting in the ground. He explained that he had to grow his tomatoes in tubs on wheels so that every day he could push them around to catch the few wan rays of sunlight that managed to drift halfheartedly through the leaves of the mammoth London plane trees overhanging our backyards. It seemed I had made a classic novice gardener’s mistake—I was trying to grow plants with total disregard for their needs.

Life became a quest for species that would grow in the low light of what was indisputably a shade garden. On the long tour up the learning curve I finally came across a lovely flower that would work with the nondescript ferns and hostas which, up to that point, were the only things I was able to keep alive. Thus began my love affair with astilbes.

My first astilbe was a tall plume in a plush shade of  fuchsia with deeply cut dark green leaves, and when I added it to my garden I suddenly had texture and color and hope.

Further proof of its worth: my first astilbe didn’t even succumb to the hordes of slugs that were waging war on the hostas.

Cheat Sheet

• Astilbes need plenty of water to thrive and are good candidates for waterside plantings, shady woodland gardens and boggy areas.
• Although mainly known as shade plants, astilbes will tolerate full sun if they are grown in rich acidic soil that is kept moist.
• There are literally hundreds of varieties of astilbe and they come in a limitless array of heights, from very short to quite tall. But they almost never need staking.

Keep It Alive

• Astilbes love cool climates but, with adequate watering and mulching, will grow in USDA zones 3 to 9.
• If plants scorch in summer drought, cut them back to the ground. Fresh regrowth will appear when the weather turns cooler.
• It may seem contradictory but moisture-loving astilbes cannot survive in soggy winter soil.  Make sure your plants have adequate drainage.
• Astilbes are clump-forming and will lose vigor if they are not divided every three to four years, preferably in early spring.

In an essay that appears in his 1992 collection, The Gardener’s Eye, garden writer Allen Lacy declared that he liked “astilbes very much indeed” and gave clear instructions on how to go about dividing them. “Using a sharp knife,” he directed, “cut their woody crowns into three or four pieces, each with three or more eyes.” He labeled this task a “chore” but pointed out that division produces more plants to enjoy in the garden as well as to share with friends.

Drawing on his experience of gardening in rural southern New Jersey, Lacey also suggested removing mulch in winter to avoid encouraging destructive voles and meadow mice to take up underground residence in astilbe rhizomes.

See more growing tips at Astilbes: A Field Guide to Planting, Care & Design in our curated guides to Perennials 101 and Bulbs & Tubers 101. See more ideas for designing shade gardens:

• How to Garden Like a Frenchman: 10 Ideas to Steal from a Parisian Courtyard
• Steal This Look: Shady Secrets of an Expert Gardener
• Coral Bells: A Field Guide to Planting, Care & Design
• Ask the Expert: Design Tips for a Shady Courtyard Garden
• Hostas: A Field Guide to Planting, Care & Design