“If you've got a shade garden, black cohosh (Actaea racemosa) is an absolute must-have — and here's why: it actually blooms in mid- to late summer, when most shade plants have already called it quits.…”
Astilbe montana
Black Cohosh Contributes Dramatic Summer Flowers to the Shade Garden
If you've got a shade garden, black cohosh (Actaea racemosa) is an absolute must-have — and here's why: it actually blooms in mid- to late summer, when most shade plants have already called it quits. Those incredibly tall white flower spikes are real showstoppers, and pollinators think so too. On top of that, its big mound of bold, textured green foliage does a fantastic job of smothering weeds and creates a gorgeous contrast with finer-leaved or variegated shade companions.
Common name: Black cohosh, bugbane, black snakeroot, fairy candles
Botanical name: Actaea racemosa; previously Cimicifuga racemosa
Origin: Woodlands across much of the eastern United States and Canada — it's right at home in the forest.
Flowers: From mid- to late summer, bottlebrush-like flowers open on tall stems that hold them well above the foliage — we're talking four feet or taller. The stems are pretty sturdy, but if the plant's in deeper shade, they may lean and reach toward whatever light they can find. Butterflies, moths, and bees all visit the flowers.
Foliage: The compound leaves are medium green and made up of lots of toothed leaflets, giving the whole plant a coarse, bold texture — kind of like a really big astilbe. If you want something with darker leaves, the cultivars 'Brunette' and 'Atropurpurea' have gorgeous purple to bronze-tinged foliage.
Size and habit: Actaea racemosa is an herbaceous perennial that grows almost like a small shrub. It forms a rounded mound of leaves about two to three feet tall and wide, and when it flowers, the total height can double. This two-tiered habit is actually really handy for placement — you can tuck black cohosh in front of companions that are similar height or taller than its foliage mound, and the airy flower stalks still let you see through to the plants behind.
Growing black cohosh
Exposure: Part shade, dappled light, or full shade
How to grow it: Plant Actaea racemosa where it gets fewer than four hours of direct sun a day — and definitely avoid afternoon sun, which can scorch those beautiful leaves. This woodland beauty will grow and flower happily in all-day dappled light or even full shade. It loves rich soil that stays consistently moist. Give it those conditions and it's basically carefree. It can be a little slow to settle in and reach its full glory, but once it does, it's a long-lived, reliable shade garden star. It may slowly spread by rhizomes to fill gaps, but it's not aggressive at all. USDA Zones 3–8.
