By Cindy Gilberg
Missouri is home to a long list of native shrubs and small trees, many of which are prime choices for our landscapes. According to Don Kurz (author of the field guide “Shrubs and Woody Vines of Missouri”), approximately 130 species of small to medium native woody shrubs can be found growing in our state. While this doesn’t include several of the small trees, some are species we might think of as small trees rather than as shrubs. There is a fine line distinguishing between small trees and shrubs – in general, trees have single trunks and are about 20 feet or more in height while shrubs have multiple stems. Of course, gardeners sometimes confuse the situation even more by encouraging multiple stems on small trees and by pruning shrubs into single-stem specimens.
As versatile as they are functional, this group of plants is an integral part of the overall landscape, adding medium-size, year-round structure. Between the canopy of large trees and the herbaceous plants that form the ground layer, shrubs and small trees provide the framework or backbone of the garden. In this way, they are useful in outlining the structure of a space. Many designers use them to create ‘rooms’ within a garden as well, providing enclosure and privacy.
Shrubs and small trees are quite valuable as screening and are an aesthetic alternative to fencing, especially when the fence is not tall enough to successfully block the view. Consider combining groups of different species with varying heights and textures for a more dynamic setting. Repetition of similar forms throughout the view creates rhythm and serves to tie the garden together visually. A few species that work well for screening are hazelnut (Corylus americana), black haw (Viburnum prunifolium), gray dogwood (Cornus racemosa), and ninebark (Physocarpus opulifolius). These species are also outstanding choices for planting after invasive honeysuckle is removed, particularly when the invasive bush honeysuckle is functioning as a screen.
Smaller shrubs (three to five feet) can be planted in large masses to form tall ground cover, making a handsome backdrop for shorter herbaceous perennials. A classic look is to have small trees rising up out of these masses, using the ground cover shrubs as an anchor for the scene. A useful list for this situation includes fragrant sumac (Rhus aromatica ‘Grow Low’), beautyberry (Callicarpa americana), wild hydrangea (Hydrangea arborescens) and golden currant (Ribes odoratum).
All of these plants can be used as accents in the garden where textural contrast is needed or to punctuate a view. Leatherwood (Dirca palustris) is a lesser known beauty that is slow-growing, reaching an ultimate height of five to six feet. Vernal witch hazel (Hamemalis vernalis) blooms in late winter with dark-yellow flowers that are delightfully fragrant while common witch hazel (H. virginiana) blooms with lemon-yellow flowers in late fall. Both grow 12 to 15 feet tall but give vernal witch hazel lots of space since it grow 15-20 feet wide as well. Both have desirable yellow-orange fall foliar color.
Remember that habitat for birds and other wildlife is best accomplished with a diversity of plants. Make note of when a plant flowers, attractive for both the gardener and pollinating insects. Many have berries, such as dogwoods, viburnums and spice bush (Lindera benzoin), providing additional interest in the garden as well as food for birds. Dense branching of shrubs and small trees also offers cover and potential nesting sites for many birds.
Most gardeners know the classic ‘top ten’ that include dogwood, redbud, serviceberry, fringe tree and winterberry. Just a handful of other worthy options for the landscape are discussed here. The Native Plant School, held at Shaw Nature Reserve, has a new three-part class this year – Native Small Flowering Trees and Shrubs. This is a wonderful way to become familiar with a whole new palette of hardy native plants.
Cindy Gilberg, horticulturist and Missouri native, founded and ran the garden center at Gilberg Perennial Farms with her husband Doug for 28 years, also teaching classes and workshops on gardening and garden design. She now focuses on garden design, consulting and teaching, and also works part-time in the Whitmire Wildflower Garden at Shaw Nature Reserve, emphasizing the use of native plants in home landscaping.