There is a good reason why astilbe is the traditional perennial flower for half-shade gardens—it is dependable, beautiful, and easy to grow. Known for mounds of ferny foliage and flower plumes rising on slender, upright, or arching stems, astilbes come in flower colors that include white, pink, red, and reddish purple. Astilbes have many hybrid varieties that vary in size, height, type of flower, and time of bloom. You can have short astilbes in front, and in the rear of the garden bed have 3-foot-tall varieties, such as ‘Purple Candles.’ All are deer resistant and thrive in part-shade, well-watered conditions.
Astilbes are the backbone of part-shade gardens. They make quite a show when planted in a large mass. You can also combine them with other moisture-loving shade plants such as ferns, Japanese forest grass, hellebore, brunnera, and hosta. For the front of a border, plant a group of short, 12-inch-high ‘Sprite’ dwarf astilbe (Astilbe simplicifolia ‘Sprite’) with its elegant, bronzy leaves. This astilbe has feathery, shell-pink plumes in mid- to late summer. It was named the PPA 1994 Perennial Plant of the Year. In fall, its rust-colored seed heads are notable.
To create a garden with extended astilbe bloom, select several varieties with different bloom times. For example, for a late spring or early summer bloom time, plant ‘Fanal’ astilbe with its deep red blooms and ‘Rheinland’ astilbe, which has panicles of clear pink flowers on upright, reddish stems that grow to 24 inches tall. They bloom for two to three weeks. For blooms in midsummer, try the purple-plumed Amethyst astilbe and the pure white ‘Deutschland’ astilbe.
Late summer astilbes include the fluffy purple plumes of dwarf Chinese astilbe (Astilbe chinensis var. pumila). Astilbes also make wonderful dried flowers. Leave a few spent flower blossoms on the plants and enjoy the brown spikes through much of the winter.
Astilbes look best in groups, and the fernlike foliage stays fresh-looking throughout the summer. Here, the airy flowers of astilbe ‘Deutschland’ (Astilbe × arendsii ‘Deutschland’) are planted in a large mass. The flowers reach 2 feet tall, adding drama to the landscape. The flowers are excellent for cutting. These midsummer bloomers blends well with columbine (Aquilegia), bleeding heart (Lamprocapnos), and Siberian bugloss (Brunnera). Astilbe resists diseases, slugs, and deer. Zones 4–9.
Astilbe ‘Rheinland’ is one of the most beautiful astilbes, especially when planted in mass, as shown here. Its plume flowers are a showy, clear rose-pink above dark green, finely cut foliage. Blooms in early to midsummer to 24 inches tall. ‘Rheinland’ looks striking at a woodland edge, in a shade garden, or by a pond. Deer resistant. Zones 3–9.
The raspberry-red tubular flowers of ‘Tutti Frutti’ hyssop (Agastache ‘Tutti Frutti’) loom over the garden on 3- to 4-feet-tall spikes from July–September. The flowers have a long bloom period and attract hummingbirds, butterflies, and other insects. Trim spent blossoms and more blooms will appear later in the growing season. Zones 6–9.
‘Golden Jubilee’ giant hyssop (Agastache rugosa ‘Golden Jubilee’) combines golden yellow foliage with lavender-blue flowers. It is an upright perennial that grows to 2 to 3 feet tall. It is native to Asia. Fragrant, tubular, violet-pink flowers bloom summer–fall atop strong, rigid stems. Pinch in June to keep plants full and compact if desired. Zones 5–9.