Ecosystem Health > Invasive and Noxious Plants
In recent years, an increasing number of nonnative plants have invaded forest, woodland and range habitats and threatened the native landscapes of the southern United States.
Texas is one of the primary target areas, due to this state's size and diversity of habitats. Many non-native plants are already well established in the Texas landscape. These include salt cedar, giant reed, Chinese tallow, KR bluestem grass, Chinaberrytree, Chinese privet, Asian bamboo, Russian olive, and tree of heaven.
Other invasive non-native plants that are well established in other southern states where they are causing economic impacts to woodland and range habitats have recently been detected in Texas. Among these, of greatest concern are kudzu, cogongrass, Japanese climbing fern, giant Asian dodder, Napalese browntop, climbing yams, Chinese silver grass and tropical soda .
A third category of invasive non-native plants are those species present in other states that are threatening to enter Texas, but have yet to arrive, as far as we know. These include Japanese knotweed, porcelain berry and multiflora rose, among others. Without doubt, invasive nonnative pests, be they plants, insects, animals, or diseases, are a relatively new threat to Texas forests, woodlands and ranges that are demanding greater attention by land managers and resource agencies.
Among non-native plants currently impacting Central Texas, some of the worst invaders are as follows:
Salt cedar (Tamarix spp.): This is an evergreen shrub that invades desert stream-side communities, including those along the Pecos and Colorado rivers in West Texas (Fig. 1a). The plant excretes salt from its leaves (thus the name salt cedar). Invasions of salt cedar change soil salinity, reduce water flow from streams, and displace native plant communities.
Giant reed (Arundo donax): This plant, also called giant cane, has corn-like stalks that may reach 20 feet in height (Fig.1c). The hairless stems bear long, narrow leaves that droop at the ends. Terminals form dense plumes of flowers up to 36 inches long. Dense thickets of giant reed are common throughout Central and South Texas, particularly adjacent to streams and along fencerows.
Chinese tallow (Triadica sebifera): Introduced from China in the mid-1800s as an ornamental, it has escaped cultivation and invaded a diversity of rural and urban habitats in East and Central Texas (Fig.1d). Mostly evergreen, this shrub forms dense thickets. Leaves are borne in an opposite arrangement, with smooth margins. White, fragrant flowers bloom in the spring and produce clusters of deep purple berries by fall.
Chinaberry (Melia azedarach): Native to China and Europe and brought to U.S. as an ornamental in the early 1800s, this tree has dark green, doubly compound, alternate leaves with serrated (toothed) margins (Fig.1e). The fruit is round, about ½ inch in diameter, yellow, and persists on the tree throughout the winter. It is common along roadsides and frequently planted as an ornamental.
Landowners should learn to distinguish invasive, non-native plants from native species and manage their lands to favor native vegetation. Invasive species should be detected in an early stage of establishment and removed from the landscape wherever feasible. Mechanical or chemical methods (i.e., use of registered herbicides) are available to address most invasive plants encountered in Texas. For more details on invasive plants in Texas, including distribution maps, visit the partnership web page at http://www.texasinvasives.org/.