A buttonbush is a deciduous or evergreen shrub with creamy flowers that have a musky scent. Buttonbush, Cephalanthus occidentalis, grows in Zones 5-11. Get facts and info on growing and caring for buttonbush shrubs.
Buttonbush grows 3-8’ h x 3-6’w. It requires careful siting because of its need for wet soil and its late growth in spring. It is best reserved for wet areas in naturalized situations. To naturalize it beside a pond, plant it just at the edge so it will be inundated in spring but be out of the water in summer.
Away from water in more formal situations, prune young shrubs to one trunk or two and remove dead twigs as needed in winter. Left unpruned, it becomes a loose, gangly shrub. In moist soils in a garden situation, plants can develop into small trees with smooth bark. Leaves emerge late in spring, and will sometimes look lifeless until mid-May. Leaves cluster toward the outer canopy, making this shrub ideal for underplanting with moisture-loving perennials and ground covers.
Flowers and Fruit of the Buttonbush
The globular creamy white flowers have a musky sweet scent. The 1-1/2” spheres have a tropical look and are produced throughout the summer. They are a nectar source for several types of butterflies. Fruits start out red and turn into a rounded mass of nutlets persisting through the winter. Birds and waterfowl also eat them which makes this a great shrub for attracting wildlife.
Older stems will take on a reddish-brown color. In colder parts of Zone 5, buttonbush dies back in severed winters and can be treated as a perennial in a mixed border. Cut it back to 6-12” every winter and it will regrow into a 3-4” rounded mound by flowering time. Flowers come from new growth so hard pruning will not eliminate them.
Care of Buttonbush Shrubs
Plant the shrub in moist to wet conditions in full sun. It will not survive in dry conditions. To plant this shrub in sandy soil, incorporate abundant organice matter such as peat moss, compost, or well-rotted manure before planting to improve water retention. This shrub requires moist or wet soil throughout the growing season and needs supplemental watering during dry periods. A 2-4” layer of organic mulch of wood chips or shredded bark will help conserve moisture.
An annual application of plant food, such as Miracle Gro, in spring produces the best flowers. It needs rejuvenation pruning every spring or so to maintain its form and vigor.
Propagation is done by taking softwood or hardwood cuttings. Seeds will germinate without pretreatment.