Delft Lace Astilbe is a superb addition to eastern exposures with consistent moisture. Its blue-green foliage has a silver overlay in shaded gardens but will develop attractive purple-red margins in locations receiving direct morning sun. The foliage texture is similar to ‘Vision’. Deep salmon-pink flower buds open to a soft apricot-pink on red stems, giving a two-tone effect. Excellent intermediate texture between ferns and hostas for the shade garden.
Although beautiful in the shade garden, astilbe flowers are not significant nectar and pollen sources for pollinators. The foliage is pubescent (fuzzy) and is typically deer and rabbit resistant.
Like all astilbes, Delft Lace Astilbe requires consistently moist soil and should not be allowed to dry out. Using 2-3 inches of mulch will help retain moisture, as will adding organic matter to the soil when planting. If planting on an eastern exposure with 4 hours of sun, more frequent watering may be required to prevent scorching.
While the flowers of Delft Lace Astilbe are excellent for cutting, this does not extend or improve the plant’s bloom period. Alternatively, you can leave the spent flower heads on the plant through winter for interest.
Astilbes, Delft Lace included, should be divided every 3-5 years as the clumps fill out. Division is most successful after the flowers have faded, but it is more important to adequately water the new transplants after division. Fertilizer is not typically necessary for the plant to do well.
Powdery mildew can be problematic on astilbe if the leaves are constantly wet. This is commonly due to overhead watering. If observed, change your watering routine so that moisture goes directly into the soil rather than sitting on the leaves. Although rare, the leaves are sometimes browsed by Japanese beetle. This damage is rarely problematic.
In periods of high temperatures, drought, or shortly after division, the foliage can irreversibly wilt or brown. Avoid this by amending soil with compost when planting and maintaining a 2-3 inch layer of mulch. Keep the plant well-watered in periods of excessive heat. If your plant prematurely wilts during its first season, make sure the soil remains moist (but not wet!). The plant could be exhibiting transplant shock and simply spending its energy on root growth.
Astilbes are salt sensitive, so avoid planting them in areas with heavy foot and vehicle traffic in winter.
Although we list astilbe cultivars as “partial sun to full shade” plants, they can grow in full sun locations (6 or more hours of direct light per day). We even have a mass of Delft Lace Astilbe on the east side of our Retail & Landscape Office at our Menomonee Falls location. The trick is to make sure the site never dries out. In our case, we have the luxury of multiple horticulturists who can water a stressed plant at a moment’s notice. But if you’re the type of gardener to ‘plant it and forget it’, steer clear of mixing astilbes and full sun.
Pair Delft Lace Astilbe with other plants of similar moisture requirements. Blending it with other astilbe cultivars is always a solid choice, but don’t be afraid to mix in Brunnera, Turtlehead, and Bleeding Hearts with your new plants. For a more natural look, use Delft Lace Astilbe to bridge the texture gap between Ferns and Hostas in a woodland garden. Be careful when adding dry-shade plants like Coralbells as this could lead to long-term conflicts in moisture needs.