With a burgeoning horticultural market introducing new species of ornamental landscape trees, some of those trees have become invasive, producing copious numbers of pesky offspring that take over gardening areas and push out native species. But while the new and unique is always eye-catching in plant nurseries, native and less invasive trees can provide just as much WOW factor as introduced plants.
The new and flashy species are always catnip to gardeners, but native species can be just as outstanding. Unfortunately, they are often overlooked. Natives have the major benefit of already being adapted to environmental factors including temperatures, moisture levels, diseases, and pests. Red maples (Acer rubrum), native to the east, provide leafy, delicate foliage in summer, vivid color in fall and interesting bare bark in winter. Red maples are hardy in U.S. Department of Agriculture plant hardiness zones 3 through 9. The burr oak (Quercus macrocarpa) is an interesting tree, hardy in zones 3 through 9, that produces pointed leaves and acorns encased in a unique fringed cap. In the west, the California black oak (Quercus kelloggi) has nice golden fall color and is hardy in zone 8.
Deciduous noninvasive landscape trees should provide interesting foliage in the summer as well as intriguing bark when bare. The bald cypress (Taxodium distichum) fits that bill and is hardy in zones 5 through 10. Feathery, light green foliage turns reddish brown in the fall before falling in a blanket around the base of the tree. The bark is reddish and striated, and the overall growth pattern is slightly pyramidal, making it a beautiful specimen tree. The tupelo or sour gum (Nyssa sylvatica) is native to the southeastern United States and thrives in swampy conditions, making it a niche species. It also makes for an interesting subject in winter when its twisted branches and red-tinged bark make a striking bare silhouette. The tupelo is hardy in zones 5 through 9. The southern red oak (Quercus falcata) provides bright, red leaves in the fall and is hardy in zones 6 through 9.
Evergreens are year-round joys, providing not only a welcome respite to the winter landscape but also shelter and sometimes food for birds and other wildlife. While evergreens are seldom invasive, a sure-fire cooperative species is the southern live oak (Quercus virginiana). These oaks are fast-growing and long-lived, retaining their dark-green, waxy foliage despite winter ice or summer hurricanes, and they are hardy in zones 7 through 10. The bronze loquat (Eriobotrya deflexa) is an easily trained tree that produces bronze juvenile leaves that turn to a deep, dark green. This loquat is hardy in zones 9 through 10.
Ah, the joys of summer and spring flowering trees. One of the most beloved and most welcome is the eastern redbud (Cercis canadensis). Clusters of delicate rosy pink blooms peek out along roadways and forest edges. Heart-shaped, light green leaves quickly follow and then beanlike seed pods in summer. The redbud is hardy in zones 5 through 9. The tulip tree (Liriodendron tulipifera) is a large tree, reaching 100 feet in height; it is hardy in zones 5 through 9. Foliage starts out as small, yellowish-green leaves with large, lobed edges that turn a darker green and finally a brilliant yellow in the fall. The flowers are tulip-shaped -- hence the name -- with interesting and intricate structures.
- The Plant Book; Geoff Bryant
- University of Connecticut: New England Invasive Plant Center
- California Invasive Plant Council: Don't Plant a Pest Brochures
- CalPoly: Urban Forest Ecosystems Institute: Red Maple
- CalPoly: Urban Forest Ecosystems Institute: Southern Red Oak
- CalPoly: Urban Forest Ecosystems Institute: Burr Oak
- CalPoly: Urban Forest Ecosystems Institute: California Black Oak
- CalPoly: Urban Forest Ecosystems Institute: Bald Cypress
- CalPoly: Urban Forest Ecosystems Institute: Sour Gum
- CalPoly: Urban Forest Ecosystems Institute: Southern Live Oak