Controlling Invasive Shrubs in Wetlands and along Streams
Thorough guidelines for controlling each of the following species can be found in Cherri Smith's manual distributed by N.C. Department of Transportation.
Please follow this link to get this FREE manual:
http://www.ncdot.org/doh/preconstruct/pe/neu/NEUProcedures/NCDOT_Invasive_Exotic_Plants.pdf
Ligustrum japonicum (Japanese Privet)
Photo credits: Rebekah D. Wallace, Bugwood.org
Japanese privet is widely dispersed throughout the southeast and the midwest, including in North Carolina. It is most common in moist forests but it also tolerates drier conditions in the upland. Wildlife, especially birds, are most responsible for seed dispersal.
Japanese privet is an evergreen shrub that grows up to 20’. Glossy leaves (2 – 3” long) are elliptical and oppositely arranged on the stem. Small white, fragrant flower clusters bloom in midsummer. Fruits are blue to black, small, and oval-shaped. They ripen in the fall.
Ligustrum sinense (Chinese Privet)
Photo credits (left to right): Troy Evans, Great Smoky Mountains National Park, Bugwood.org; Chris Evans, River to River CWMA, Bugwood.org
Chinese privet grows along roadsides, in woods, bottomlands, and along streams in the Piedmont and in all other parts of the state. It can form dense thickets which effectively wipes out the herbaceous vegetation.
The shrub produces a small black fruit in late summer, early fall which is consumed by birds; birds are the most effective dispersers for this aggressive plant. Besides the black fruit, the shrub can be identified buy its oval-shaped leaves which grow oppositely along the branches. The leaves are dark and glossy on the top surface and pale on the underside with a hairy midrib. The shrub grows up to 15' and has smooth gray or tan bark. In mid-summer, the tree produces small white flowers which grow in clusters at the end of each branch.
The shrub produces a small black fruit in late summer, early fall which is consumed by birds; birds are the most effective dispersers for this aggressive plant. Besides the black fruit, the shrub can be identified buy its oval-shaped leaves which grow oppositely along the branches. The leaves are dark and glossy on the top surface and pale on the underside with a hairy midrib. The shrub grows up to 15' and has smooth gray or tan bark. In mid-summer, the tree produces small white flowers which grow in clusters at the end of each branch.
Reynoutria japonica (Japanese Knotweed)
Photo credit: Leslie Seiger, San Diego Mesa College, Bugwood.org
Japanese knotweed has invaded the eastern United States and southern Canada. In the mountains and in the Piedmont of North Carolina it is most common in open habitat along streams and in floodplains. It disperses mainly as seeds and rhizome fragments through flooding.
Japanese knotweed forms small shrubs (10’) with smooth hollow stems, reminiscent of bamboo. Its leaves (6” long and 3 – 4” wide) are oval but taper to a point. Small, white flowers grow in spikes in late summer and early fall.
Japanese knotweed forms small shrubs (10’) with smooth hollow stems, reminiscent of bamboo. Its leaves (6” long and 3 – 4” wide) are oval but taper to a point. Small, white flowers grow in spikes in late summer and early fall.
Rosa multiflora (Multiflora Rose)
You can distinguish this rose from native
wild roses by its feathery stipules. Photo credits (from left to right): James H. Miller, USDA Forest Service, Bugwood.org; Chris Evans, River to River CWMA, Bugwood.org
Past efforts to use this rose shrub as live fencing in pasture land has made it a problem in current pasture lands, successional fields, and in other open habitats throughout the state.
The shrub grows to 10' and has arching, thorny stems. The compound leaves are made up of 7 to 9 leaflets (1 - 1.5") arranged in an alternating fashion along the leaf stem and a terminal leaflet. The leaflets are oval with serrated edges. A distinguishing feature is that the stipules, the green growths at the base of leafstalks, are feathery. The 5-petaled flowers bloom in May or June and are fragrant, white or pink, and about 1" diameter. Bright red rosehips develop during the summer and can stay on through the winter. As they dry out they become leathery and brown.
The shrub grows to 10' and has arching, thorny stems. The compound leaves are made up of 7 to 9 leaflets (1 - 1.5") arranged in an alternating fashion along the leaf stem and a terminal leaflet. The leaflets are oval with serrated edges. A distinguishing feature is that the stipules, the green growths at the base of leafstalks, are feathery. The 5-petaled flowers bloom in May or June and are fragrant, white or pink, and about 1" diameter. Bright red rosehips develop during the summer and can stay on through the winter. As they dry out they become leathery and brown.
Spiraea japonica var. fortunei (Japanese Spiraea)
Photo credit: Great Smoky Mountains National Park Resource Management Archive, USDI National Park Service, Bugwood.org
Japanese spirea has dispersed throughout the eastern United States, including in the mountains of North Carolina. It is most common in moist, open forests. Seeds are dispersed through water, making it common along stream banks.
Japanese spirea has beautiful pink flowers which make it a popular ornamental. These flowers grow in clusters in midsummer. Leaves are oblong and serrated (1 – 3” long). The shrub grows to 3 - 6’ tall.
Japanese spirea has beautiful pink flowers which make it a popular ornamental. These flowers grow in clusters in midsummer. Leaves are oblong and serrated (1 – 3” long). The shrub grows to 3 - 6’ tall.
Tamarix ramosissima (Salt Cedar)
Photo credit: Steve Dewey, Utah State University, Bugwood.org
Salt cedar is an invasive from Africa that is mostly a problem in western and central United States but it is also invasive in the south’s riparian zones, wetlands, and coastal areas.
Salt cedar can grow between 5 – 20’ in height. The bark of young trees is smooth and reddish but it grays and becomes rougher as the shrub ages. Tiny grayish-green leaves overlap along the stem. Pinkish white flowers bloom from spring to late summer.
