Astilbe flowers have their tall, fluffy plumes that tower above frilly, fern-like foliage in the shade garden. These attractive flowers make great companions for other shade-tolerant plants, such as hosta and hellebores, with contrasting foliage and coordinating blooms.
Twenty-five species of Astilbe exist, with hundreds of hybrids available. Some are borne on arching stems, while others are erect. Astilbe flowers range in color, from whites to dark purples, though most are pastel. Astilbe flowers may be a few inches to a few feet in height, depending on the astilbe plant you choose.
Astilbe plants grow in shade, but flowers are more productive in an area where gentle morning or dappled sun (think Gerard Manley Hopkins) can reach them for about an hour or two. Astilbe flowers also need correct soil and moisture to flourish. Astilbes prefer rich, organic type soil. Organic material such as compost enriches the soil and adds drainage. If your shady areas have poor, lean or rocky soil, work in some compost a few weeks before putting your plants in the ground. Amend the soil 8 to 12 inches deep so that the roots of astilbe flowers have plenty of room to develop. Place the astilbe plants into the soil, keeping the crown at the same level as the top of the soil. Water well when planting and keep the soil consistently moist.
Care for astilbe includes regular, even watering throughout its active growth, especially if planted in areas with more sun. Drying out can lead to leaf scorch, drying leaf margins and can even be the death of the astilbe plant. The right astilbe growing conditions and fertilizer result in large feathery plumes. Occasionally amending the soil with compost or fertilizing with an organic product or fertilizer high in phosphorus is also recommended. Spent plumes can be cut back in spring or left alone for winter interest. They can also be divided about every four years as needed. Proper care for astilbe plants and the right location can result in delicate, long-lasting blooms in the spring and summer garden.