Garden Worthy Willows
There is perhaps no native plant more ubiquitous than willow, especially black willow (Salix nigra). It comes up in house gutters, garden beds, low farmers’ fields, roadside ditches, pond margins and every creek-side gravel bar in the eastern half of the United States.
By Scott Woodbury
[This article was first published in The Gateway Gardener March 2020 issue.]
“Between the ranch house and the house we live in is the singing creek where the willows grow. We have conversations, and there I do dabble my toes beside the willows. I feel the feels of gladness they do feel”. Opal Whitely, The Singing Creek Where the Willows Grow
There is perhaps no native plant more ubiquitous than willow, especially black willow (Salix nigra). It comes up in house gutters, garden beds, low farmers’ fields, roadside ditches, pond margins and every creek-side gravel bar in the eastern half of the United States. Why house gutters? Their seeds are like Who-ville specks flying on the wind in late spring (see Dr. Seuss, Horton Hears a Who). They produce millions and millions of fluffy air-born seeds that may fly for miles. Those that land on disturbed wet bare soil or gravel, sprout immediately and grow fast. Salix literally means “jump” in Latin. There is no need for a cold winter to break seed dormancy. Seedlings grow rapidly to stabilize creek and river edges that get scoured from spring rainstorms; natures living Band-Aid. But as useful as black willows are in healing damaged creeks, they are thought of as weeds in the landscape. They grow quickly to thirty feet, which is too large for most gardens.
Fortunately there is prairie willow (Salix humilis), a small clump-forming shrub that grows about five feet tall with branches that extend horizontally as the plant grows. It has a slow-to-moderate growth rate and will form a small colony over many years. When pruned every other year, plant height may be reduced. It blooms in early March, coinciding with the emergence of early-season bees and flies that are hungry for its abundant pollen and nectar. It also is the favorite food of mourning cloak and red admiral butterflies whose caterpillars feed on the leaves in summer. It is an upland willow species, growing in dry prairies and a good choice for difficult low-maintenance dry landscapes. It may be grown as a low hedge or mass, as it tends to grow outward more than upward, like ‘Gro Low’ aromatic sumac. It also grows densely with a profusion of slender stems, eliminating weeds effectively. There are eco-types of prairie willow that grow much taller so look for the low-growing form of prairie willow from Shaw Nature Reserve called the ‘Brazil’ strain (discovered near Brazil, Missouri) at the Spring Wildflower Market on Mother’s day weekend.
Heart-leaved willow (Salix eriocephala) grows wild in wet woodlands, wetlands and along creeks. In gardens it thrives in sun or part shade and clay soils, wet or dry. The variety growing in the Whitmire Wildflower Garden grows similarly to the ‘Brazil’ strain of prairie willow but is slightly bigger, growing six to eight feet tall. Branches grow laterally and root at the edges as the plant expands outward at a slow to moderate rate. Butter-yellow flowers emerge in spring from reddish flower buds and stems. It has the showiest buds, flowers and stems of the Missouri willow species and has potential for cut-flower use.
Sand-bar willow (Salix interior) is a showy shrub for landscaping with the potential to reach eight feet in height and greater in width, making an excellent screen. It is twiggy and dense in form, eliminating weeds effectively. Sand-bar willow has showy narrow drooping leaves that are very long, dark-green and narrow, kind of like vanilla beans hanging down from the stem.
Carolina willow (Salix caroliniana) will grow into a twenty-foot tall and wide tree that resembles a weeping willow. Its juvenile yellow branches are flexible and move in the wind. To train one into a tree, remove all but one to three of the most vigorous stems and limb it up (remove lower side branches and sprouts) to a desired height during the first three to five years of growth. It is both flood and drought tolerant. For gardeners, that is key because weeping willows suffer from drought. To grow as a screen, cut it back to the ground annually to form an impenetrable clump of stems and leaves eight to ten feet tall and wide. Carolina willow is a fast-growing species.
Horticulturist Scott Woodbury is the Curator of the Whitmire Wildflower Garden at Shaw Nature Reserve in Gray Summit, MO, where he has worked with native plant propagation, design, and education for 25 years. He also is an advisor to the Missouri Prairie Foundation’s Grow Native! program. Find suppliers of berry-producing native plants at www.grownative.org, Resource Guide.