Buttonbush

Size, growth and what to expect

Buttonbush grows at a medium pace, about a foot and a half a year in our growth estimator. Expect a shrub 5 to 12 feet tall and about as wide, on several stems from a swollen base. In the South it can grow into a small tree of 15 to 20 feet. It is often long-lived.

Round white flower heads open from June to September, each an inch to an inch and a half across. The fruiting heads ripen reddish brown in September and October. Many hang on through winter, when birds eat the nutlets. The flowers feed butterflies, bees and hummingbirds, and more than 24 kinds of birds visit the shrub.

It grows wild from Nova Scotia and Quebec west to Minnesota and south to Florida and Texas, with scattered stands west to Arizona and California's Central Valley. Its home is swamps, marshes, pond shores and stream banks that stand in water for part of the year.

How to grow Buttonbush

Buttonbush wants full sun or part shade and a soil that stays moist to wet, and it grows in standing water up to 3 feet deep. It takes clay, heat and compacted ground, but not a dry bed, and it flowers poorly in shade. Set plants 4 feet apart and keep them 6 feet from a wall. At its size it can go within 15 feet of overhead wires.

Saplings ship bare-root or potted. Plant them dormant, from leaf fall until bud swell, in a hole wider than the roots and no deeper. Set the crown at the soil line, put the native soil back in, and keep the mulch clear of the stems. Pick the fruiting heads in fall once they turn reddish brown, and break them apart when dry. The seed needs no treatment. Sow it in spring on the surface of moist soil, barely covered, and keep it damp.

Water weekly through the first summer unless it stands in wet ground, and in any drought after that, since dry spells make it die back. Its leaves come out late in spring, so give a new plant time before taking it for dead. Deer browse the foliage in the North, so cage young plants where deer are many. It needs little pruning, and an overgrown plant can be cut back near the ground in early spring to grow again.

Each flower carries both male and female parts. Buttonbush sets little seed with its own pollen and far more with pollen from another plant, so plant two or more seedlings from different parents for seed. No pest or disease troubles it seriously, and it is a host plant of the promethea silkmoth. Its bark and leaves are poisonous if eaten, so keep it away from grazing animals.