Controlling Invasive Trees in the Mountains
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
Ailanthus altissima (Tree of Heaven)
Photo credit: Jan Samanek, State Phytosanitary Administration, Bugwood.org
The ability of the tree of heaven to tolerate poor soils makes it a common invasive along roadsides in North Carolina (and all over the country). It is common in urban areas, the mountains, and in the coastal plain.
The tree is small to medium sized with smooth gray bark. It has alternate compound leaves, with 10-40 leaflets along the leaf stem. Each leaflet is lance-shaped.
It flowers in mid to late summer. Flowers are greenish-yellow and grow in clusters. The seeds are light and spread easily through the wind; they are enclosed in a twisted papery pod.
The tree is small to medium sized with smooth gray bark. It has alternate compound leaves, with 10-40 leaflets along the leaf stem. Each leaflet is lance-shaped.
It flowers in mid to late summer. Flowers are greenish-yellow and grow in clusters. The seeds are light and spread easily through the wind; they are enclosed in a twisted papery pod.
Albizia julibrissin (Mimosa)
Photo credits (left to right): USDA Forest Service - Region 8 - Southern Archive, USDA Forest Service, Bugwood.org; James R. Allison, Georgia Department of Natural Resources, Bugwood.org
Mimosa was introduced in the 1700s and is still a popular ornamental tree but it has jumped out of the garden and moved into natural habitats throughout the United States. The tree produces shoots from root sprouts allowing it to form dense thickets which prevents native plants from growing. Seeds are dispersed by animals and through water. It grows best under full sun - so areas along roads and streams are common places for them to grow. The also grow in suburban and urban areas. It is uncommon above 3,000 feet.
The tree (up to 50' tall) is easy to identify in the spring and summer because it produces fragrant, feathery, pink flowers, which resemble pom-poms. In later summer/early fall, it produces oblong, hanging seed pods (6" long).
The fern-like bi-pinnately compound leaves (5 - 8" long) are also distinguishing.
The tree (up to 50' tall) is easy to identify in the spring and summer because it produces fragrant, feathery, pink flowers, which resemble pom-poms. In later summer/early fall, it produces oblong, hanging seed pods (6" long).
The fern-like bi-pinnately compound leaves (5 - 8" long) are also distinguishing.
Paulownia tomentosa (Princess Tree)
Photo credits (left to right): Leslie J. Mehrhoff, University of Connecticut, Bugwood.org;Pennsylvania Department of Conservation and Natural Resources - Forestry Archive, Bugwood.org
This fast-growing tree (it can grow 15' a year) competes aggressively with native species in disturbed areas in the mountains and foothills of North Carolina and other southeastern states.
It can be identified by its large heart-shaped leaves (arranged oppositely along the branches) and its pretty lavender flowers (on mature trees). The flowers grow in upright clusters during the spring. It produces sticky, green oval-shaped fruits and small, winged seeds. The tree can grow up to 50' and has smooth gray bark (with slight cracks).
It can be identified by its large heart-shaped leaves (arranged oppositely along the branches) and its pretty lavender flowers (on mature trees). The flowers grow in upright clusters during the spring. It produces sticky, green oval-shaped fruits and small, winged seeds. The tree can grow up to 50' and has smooth gray bark (with slight cracks).
Triadica sebifera (Chinese Tallow Tree)
Photo credit: leaves and flowers: Chuck Bargeron, University of Georgia, Bugwood.org; Seeds: Chris Evans, River to River CWMA, Bugwood.org, forest stand (understory): Chris Evans, River to River CWMA, Bugwood.org
This tree has invaded natural areas in other southern states but so far has remained pretty controllable in North Carolina. However, it can invade undisturbed forests so if it does get out of control it may be a serious threat to native plant communities in forests. So, please keep your eye out for the Chinese tallow tree. It grows usually to a height of 30’ but can be as tall as 60’. The leaves (2 – 3” long) are heart-shaped. Twigs are green to light brown and have small brown dots on them (lenticels). Bark is reddish-brown. In the spring, the tree produces droopy spikes of flowers. Roundish fruits with lobes appear in the summer and open in the fall to reveal popcorn-like seeds.
