PL. —Cephalanthus occidentalisBotanical illustration — drop image
Cephalanthus occidentalis

Buttonbush

Summer
5a9bHardiness zone
Peak bloom windowZone 6b · frost-offset weeks
Winter
Not in bloom
Spring
Peak bloom
Summer
Peak bloom
Fall
Not in bloom
Peak bloom
In bloom
Background

Buttonbush is a deciduous native shrub found across eastern and southern North America, growing naturally along stream banks, pond margins, and wetland edges. Its spherical white flower heads appear in midsummer and rank among the most productive nectar sources in wetland landscapes, attracting bees, butterflies, and hummingbirds in large numbers.

It tolerates prolonged flooding and can establish in standing water up to 3 feet deep, making it well suited to rain gardens, bioswales, stormwater basins, and shoreline plantings where most shrubs fail. It flowers on new wood, so late-winter pruning does not sacrifice a season's display. It spreads by root suckers and can form thickets where conditions suit it; periodic sucker removal keeps it in bounds. It leafs out late in spring, which is normal behavior, not dieback. Cold-hardy to Zone 5 and heat-tolerant into Zone 9.

Cherokee, Choctaw, and other Native peoples prepared bark infusions to treat fever, rheumatism, and eye inflammation. The foliage and seeds contain toxic alkaloids and are harmful to livestock if consumed in quantity. Ducks and songbirds eat the persistent seed heads through fall and winter, and the dense branching provides nesting and escape cover.

Care guide
SunFull sun to part shade
WaterMoist to wet
SoilMoist, wet, clay-tolerant
Spacing6–10 ft
Height6–12 ft
Zone5a – 9b
Native RegionAL, AZ, AR, CA, CT, DE, DC, FL, GA, IL, IN, IA, KS, KY, LA, ME, MD, MA, MI, MN, MS, MO, NE, NH, NJ, NM, NY, NC, OH, OK, PA, RI, SC, TN, TX, VT, VA, WV, WI
Frost hardy
Seasonal tasks
spring
cutPrune out dead or crossing stems before new growth begins; flowering occurs on new wood so late-winter pruning does not reduce summer display.
sowPlant container-grown shrubs in moist to wet soil after last frost; water deeply until roots establish into surrounding soil.
summer
cutRemove root suckers at the base with a sharp spade to prevent unwanted spread and improve air circulation around the main stems.
watchCheck new growth for aphid colonies or soft scale; treat heavy infestations with horticultural oil or a strong water spray.
watchMonitor foliage for powdery mildew during warm humid spells, especially where air circulation is poor; thin crowded stems to reduce incidence.
fall
watchLeave seed heads intact through fall and winter to provide food for ducks, geese, and songbirds; do not deadhead.
Common problems

Powdery mildew

Symptoms

White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.

Treatment

Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.

Phytophthora Root Rot

Symptoms

Wilting despite moist soil, yellowing leaves, stunted growth, and dark, decayed roots and crown tissue. Vines may collapse during hot weather.

Treatment

Plant in well-draining soil and avoid waterlogging. Remove and destroy affected vines. Improve drainage with raised beds or amended soil and avoid overwatering.