The Form, Foliage and Flowers of Buttonbush
Button It Up
By Steve Huddleston
Imagine my surprise while visiting a horticulture professor in the eastern state of Saxony-Anhalt in Germany when I discovered around the pond in his garden a large shrub/small tree native to Texas! There it was, a buttonbush! How thrilled I was to see a botanical reminder of Texas nearly halfway around the world growing just as happily under the same conditions as it did back home. You should definitely consider finding a spot in your own garden for this plant that will dazzle you with its form, foliage and flowers.
Native to Texas and most of the U.S. except the mountainous West and the Pacific Northwest in USDA hardiness zones 5-9, the deciduous buttonbush (Cephalanthus occidentalis) grows around swamps, ponds, lakes and streams throughout the state in full sun or partial shade. It adapts to a wide range of soils except dry ones and grows well in such soils as sand, loam, clay and limestone. What’s more, it grows in moist, poorly-drained soil, even soil that is submerged by as much as a foot of water. Explore the shorelines of the many lakes in Texas, and you’re bound to find buttonbush growing at the water’s edge where it assumes the shape of a large shrub. Farther up the slope from the water’s edge it takes on the shape of an even larger shrub or small tree. If you have a low, moist spot in your landscape, buttonbush will certainly thrive there. If you have a pond or bog garden in your landscape, buttonbush will look quite natural there and grow well around such water features. Buttonbush makes an ideal plant for a swale or retention pond, both of which capture rainfall and let it soak slowly into the soil as a means of conserving soil moisture and preventing run-off.
Buttonbush forms a multi-trunked, large shrub or small tree with a rounded growth habit and irregular crown that often consists of crooked and sometimes leaning branches. Buttonbush usually reaches a height of 6 to 12 feet, although it may grow taller in some instances, even up to 20 feet tall. If you want to create a tree form of buttonbush, select the strongest, most well-formed trunks to serve as the permanent structure of the tree, and remove those that are weak or superfluous. Over time, the trunks assume a rather twisted, gnarled form that lends much interest to the landscape, especially during the winter when the trunks are fully exposed. After removing undesirable trunks, you may occasionally battle a few suckers that come up around the trunk, but you can easily remove these with a pair of pruners. Buttonbush suffers from no serious disease or insect problems, although web worms have been known to create webs in the tree. If that’s the case, simply prune out the affected branch. Buttonbush is moderately resistant to deer.
Buttonbush leafs out in late spring and sports long, narrow leaves up to 8 inches long that create a lush, green canopy all summer long. The leaves appear in pairs or in threes and have a pointed tip and a rounded to tapered base, smooth margins and a glossy upper surface and a duller lower surface. The leaf margins typically curl up a little on the sides, thus creating a slightly wavy margin and cupped leaf. In the fall, the leaves turn yellow, then brown, before dropping. Once all the leaves have dropped, the picturesque structure of the twisted trunks and multi-branched, irregular crown really stands out.
The glory of buttonbush is the abundance of exotic white or pale pink flowers that appear in clusters at the ends of twigs and adorn the tree primarily in June, although the tree may continue to bloom through September. The flowers are 1-inch-wide globes with protruding pistils that make the floral spheres look like little pincushions. The flowers exude a wonderful, peach-like fragrance reminiscent of mimosa blossoms. These flowers are full of nectar that attracts bees, butterflies and hummingbirds. Buttonbush is a great plant to have if you want to encourage the production of local honey, and it’s a must for a butterfly garden. Hummingbirds enjoy roosting in the canopy of buttonbush when they’re not busy dining on the flowers’ nectar. At the end of the season, the flowers turn into little brown, button-like balls consisting of multiple, tiny, two-seeded nutlets. These seed balls persist on the tree through the winter and add interest to the exposed canopy of the tree. Ducks, other water birds and shore birds enjoy dining on the seeds. The seeds readily germinate, which means seedlings can appear in beds or turf beneath this tree.
If the species buttonbush (the one found growing in nature) is too large for your landscape, there’s now a cultivar named ‘Sugar Shack’ that grows only 3 to 4 feet tall and 3 to 4 feet wide. It has the same white, spherical flowers as the species, but the flowers turn into red fruits rather than the brown ones of the species. ‘Sugar Shack’ is the perfect size buttonbush for today’s small yards and gardens. It favors the same growing conditions as the species and makes a perfect bog plant. Because of its small size, it can also function well in a large container.
Although a trip to Germany might be something worth considering, you needn’t travel there to see buttonbush growing happily. It can grow just as happily in your own landscape where you can enjoy its form, foliage and fragrant flowers. Plant this delightful tree and let it dazzle you throughout the year!
Steve Huddleston is the senior horticulturist at the Fort Worth Botanic Garden and co-author of Easy Gardens for North Central Texas.