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What are Invasive Species?
Invasive species can range from plants to animals, and even pathogens. These invasives pose a serious threat to our native ecology and to we humans. Non-native invasive plants have been brought to the United States for various reasons, some for use as ornamentals or landscaping, others for erosion control, and some unintentionally. Non-native invasive species are usually defined as such due to the fact that they cause damage, grow rapidly, disrupt ecosystems, and out-compete native species. They can have a significant detrimental affect on a region's biodiversity and people’s livelihoods. Invasive plants frequently interfere with growth and reproduction, of native species, increasing the risk of their extinction. The damage caused by invasive plants and the attempt to manage them in the U.S. costs billions of dollars each year.
Immediate and appropriate action if taken can help to eradicate this growing problem our environment faces. Sharing knowledge of invasives with friends, family, and neighbors as well as individual action, such as removing non-native invasives on your property and encouraging those around you to do the same is the first step. One can replace invasives with native or non-invasive species, which usually fare better in the local environment, and often require less care. Reporting growing infestations and supporting local government agencies and conservation organizations that tackle this problem, as well as, by volunteering and staying involved will help rid our environment of this foreign invasion.
1.Chinese Privet (Ligustrum sinense)
Chinese privet is a semi-evergreen shrub or small tree that grows to 20 ft. (6.1 m) in height. Trunks usually occur as multiple stems with many long, leafy branches. Leaves are opposite, oval, pubescent on the underside of the midvein and less than 2 in. (5 cm) long. Flowering occurs in late spring, when small, white flowers develop at the end of branches in 2-3 in. (5-7.6 cm) long clusters. Fruit are oval, fleshy, less than 0.5 in. (1.3 cm) long, ripen to a dark purple to black color and persist into winter. Several privet species occur and they are often hard to distinguish. Chinese privet commonly forms dense thickets in fields or in the understory of forests. It shades and out-competes many species and, once established, is very difficult to remove. Chinese privet was introduced into the United States in the early 1852 as an ornamental.
2. Heavenly Bamboo (Nandina domestica)
Sacred bamboo invades forests throughout the Southeast United States. It is a small, erect shrub that grows up to 8 ft. (2.4 m) tall. Leaves are alternate, large, bi- or tri-pinnately compound with small, 1-2 in. (2.5-5.1 cm) long leaflets. Flowering occurs in the spring, when small, white flowers develop in large panicles at the ends of the stems. Flowers have 3-6 reflexed petals. Fruits are green berries that mature to a bright red. The older stems have bark with long, linear furrows. The overlapping leaf sheaths give the main stem the appearance of bamboo, hence the name. Sacred bamboo is shade tolerant, which allows it to invade forest edges and interiors. It is native to eastern Asia and India and was first introduced to North America in the early 1800s. It has been planted widely as an ornamental and often escapes from old plantings.
3. English Ivy (Hedera helix)
English ivy is an evergreen vine that can grow to 100 ft. (30.5 m) in length. Leaves are dark-green and waxy with palmate veins. Leaf shape is very variable, but commonly occurs as a 3-5 lobed leaf with a heart-shaped base. Flowering (maturity) is triggered by sunlight, such as when the vines climb into taller vegetation. In the late summer mature plants produce terminal clusters of greenish-yellow flowers. Fruits are black and fleshy. English ivy can invade woodlands, fields and other upland areas and is spread by runners. Seeds can also be spread by birds. It can grow both along the ground, where it can displace native understory species, and in the tree canopy, often covering branches and slowly killing trees. English ivy is native to Europe and was introduced into North America by early settlers for ornamental purposes. It continues to be widely planted as an ornamental.
4. Oregon Grape/Beale’s Barberry (Mahonia bealei)
Leatherleaf mahonia is an evergreen shrub that can grow from 5-10 ft. (1.5-3 m) tall. Leaves are pinnately compound, 18 in. (46 cm) long, with 9-13 holly-like leaflets. Leaflets are 2-4 in. (5-10 cm) long and 1-2 in. (2.5-5.1 cm) wide. Flowering occurs in late winter and early spring, when fragrant, lemon-yellow flowers develop. The fruits are green berries, about a half inch long, that turn bluish black with a grayish bloom. Fruits hang in grapelike clusters. Leatherleaf mahonia is native to China. It has been planted as an ornamental and is now invading woodlands in the southern United States.
5. Japanese Honeysuckle (Lonicera japonica)
Japanese honeysuckle is an evergreen to semi-evergreen vine that can be found either trailing or climbing to over 80 ft. (24 m) in length. Leaves are opposite, sessile, pubescent, oval and 1 to 2.5 in. (2.5-6.4 cm) long. Flowering occurs from April to July, when showy, fragrant, tubular, whitish-pink to yellow flowers develop in the axils of the leaves. Fruits develop in the fall and are small, shiny black berries. Japanese honeysuckle invades a variety of habitats including forest floors, canopies, roadsides, wetlands, and disturbed areas. Japanese honeysuckle can girdle small saplings by twining around them, and it can form dense mats in the canopies of trees, shading everything below. A native of eastern Asia, it was first introduced into North America in 1806 in Long Island, NY. Japanese honeysuckle has been planted widely throughout the United States as an ornamental, for erosion control, and for wildlife habitat.