WORST 10 INVASIVE PLANTS
English Ivy
Hedera helix L.
ORIGIN: Europe, Western Asia, Northern Africa
IDENTIFICATION: Evergreen woody vine, leaves dark green with whitish veins. Leaves growing along the ground are typically 3-5 lobed; leaves of climbing vines are typically unlobed. Under sunny conditions the ivy will flower (small greenish-yellow) in the later summer-early fall and then produce a blue-black berry.
HARM: English ivy harms forests from the ground to the canopy. On the ground it forms a dense thicket of ropey vines rooted in the soil and prevents other plants from growing. It climbs on trees and blocks sunlight from reaching the tree’s leaves, which weakens and eventually kills the tree. A tree covered in English ivy will generally decline over several to many years before dying. The added weight of vines also makes trees susceptible to toppling and uprooting during storms. What’s more, few native insects or birds feed on its leaves and seeds.
CONTROL: Plants can be pulled by hand, or mowed. Vines growing up tree trunks can be cut low at the ground to kill the climbing vine. Cut surfaces can be treated with systemic herbicide to kill the roots.
RESOURCES FOR CONTROLLING:
Porcelain-Berry
Ampelopsis glandulosa
Ampelopsis brevipedunculata
ORIGIN: China, Korea, Japan, Russian Far East
IDENTIFICATION: Deciduous, woody, perennial vine with alternate, simple, leaves which are heart-shaped at the base, and have 3-5 deep cut lobes. Flowers appear in summer and are small, greenish-white. Colorful berries appear Sept-Oct and are usually a mix of pink, aqua blue, purple and green. Porcelain-berry resembles native grapes, so look closely, and check resources to distinguish the two.
HARM: Porcelain-berry vines can grow up to 15 feet in a single growing season, and the seed may be viable in the soil for several years. As it spreads, it covers shrubs and other vegetation, shading out desirable plants and overtaking habitat. The vine spreads by seed (birds eat the berries and spread the seed) and by root sprouts. Porcelain berries are not a valuable food source for birds because they are low in protein and fat.
CONTROL: Hand pulling of vines before fruiting to prevent the formation and spreading of berries. For vines too large to pull, cut the vine near the ground and either treat cut stems with a recommended herbicide or repeat cutting of regrowth as needed.
RESOURCES FOR CONTROLLING:
Asian Wisterias
Japanese Wisteria - Wisteria floribunda
Chinese Wisteria - Wisteria sinemsis
ORIGIN: Japan, China, Korea,
IDENTIFICATION: Deciduous, perennial, woody ornamental vines with alternate pinnately-compound leaves. The vines typically bloom in springtime (April-May) with a showy lavender, pale blue or white, cluster of flowers. Velvety brown seed pods (4-6 inches long) are produced in June.
HARM: Wisteria vines spread by distribution of seeds and development of roots and shoots. The vines wind tightly around host tree trunks and branches, causing death of the host by girdling or by excessive weight which topples the tree.
CONTROL: Do not plant! Most infestations in natural areas are a result of escapes from landscape plantings. For existing asian wisterias, cut climbing vines as close to the root as possible. Wisteria will continue to resprout after cutting until its root stores are exhausted. Cutting in the early growing season is best, followed by cutting sprouts every few weeks until fall. Cutting and treating with an approved herbicide is also effective.
RESOURCES FOR CONTROLLING:
Wintercreeper
also known as creeping euonymus
Euonymus fortunei
ORIGIN: China, Korea, Japan
IDENTIFICATION: An evergreen woody vine or sprawling shrub, with opposite leaves which are oval, slightly toothed, glossy and 1-2 inches long. The juvenile form is a vine-like groundcover, and the adult form is a shrub. The leathery dark green leaves have silvery-white veins. It blooms May-June with small pale green flowers. Fruits are small, round white to pinkish-red, that split open to expose reddish-orange seeds in late summer to early fall.
HARM: Wintercreeper is a very aggressive vine that spreads over the ground and climbs on trees and shrubs. It forms a dense ground cover that reduces or eliminates other desirable plant species in woodlands and forests. Climbing wintercreeper can smother and kill shrubs and small trees. Wintercreeper spreads by rootlets and by seeds dispersed by birds, small mammals, and water.
CONTROL: Hand pulling of vines and roots is recommended. Vines on trees should be cut near the ground to kill climbing portions. Stems can be cut and treated with a herbicide to kill the entire plant including the roots.
RESOURCES FOR CONTROLLING:
Chinese Privet
Ligustrum sinense
ORIGIN: China. There are no privets native to the U.S. Although there are several varieties of privet, one of the most prevalent in central Virginia (and Bandy Field Nature Park) is Chinese Privet.
IDENTIFICATION: Semi-evergreen shrub, with opposite, oval or elliptical leaves, up to 2 inches long. Fine hairs are on the twigs and underside of leaves. Small white fragrant flowers grow in clusters as end of branches (May-July). Produces a small dark blue berry which matures in late summer to early fall.
HARM: Chinese privet is identified as a high-risk invasive species in Virginia. It has spread rapidly to forested areas across Virginia, including forested areas in urban parks, where it can quickly dominate the shrub layer, form dense thickets, and choke out native plant species. It spreads by both seed (birds eating the fruits) and through root sprouting.
CONTROL: Do not plant privet. Cut and bag fruits to prevent spread by birds. Remove privet from your yard. Manually remove by pulling or digging ensuring roots are completely removed. Large plants can be cut and treated with an approved herbicide.
RESOURCES FOR CONTROLLING:
Japanese Honeysuckle Vine
Lonicera japonica
ORIGIN: China, Japan, Korea
IDENTIFICATION: A twining woody vine with simple, opposite leaves 1-3 inches in length. In central Virginia, it is semi-evergreen and persists year round. It has a fragrant white or yellow flower which blooms in spring-summer. The fruit is a paired, black pulp berry that matures in early autumn.
HARM: Japanese honeysuckle vines grow and spread rapidly and can form large smothering tangles over other plants, and twine around trees and woody shrubs leading to suppression of plant growth and girdling. Negative effects also include alteration of habitats used by native wildlife. Spreads by distribution of seeds by birds and by shoots and runners.
CONTROL: Do not plant, and remove from your yard. Manually remove by pulling or digging and removing trailing vines. Repeated mowing can also be effective. Herbicide application can also be used to treat leaves in winter.
RESOURCES FOR CONTROLLING:
Bush Honeysuckles
Lonicera
ORIGIN: China, Japan, Korea, Russian Far East. There are many varieties of bush honeysuckle which have been introduced in Virginia. Two common varieties seen in central Virginia are Amur honeysuckle and Morrow’s honeysuckle.
IDENTIFICATION: Bush honeysuckles are deciduous shrubs reaching up to 20 feet high. The leaves are opposite, simple leaves about 1-3 inches long. The bush flowers in May to June with a white to pinkish flower. The fruit is a red to orange berry occurring in pairs close to the branch. Bush honeysuckle that escapes cultivation shows up along roadsides, in forest edges, and urban parks.
HARM: Bush honeysuckles spread rapidly and form dense thickets that shade out native plants, and release chemicals that inhibit the growth of other plant species. It can spread by seeds/fruits eaten by birds and by vegetative sprouting.
CONTROL: Do not plant, cut and bag fruits to prevent spread by birds, and remove from your yard. Manually remove by pulling or digging ensuring roots are completely removed. Large plants can be cut and treated with an approved herbicide.
RESOURCES FOR CONTROLLING:
Tree-of-Heaven
Ailanthus altissimus
David Morehead, University of Georgia, Bugwood.org
ORIGIN: China, Taiwan
IDENTIFICATION: Medium sized deciduous tree. Key identification features include: alternate large (1-4 ft) compound leaves with 11-25 leaflets; flowers and leaves have offensive odor likened to burnt or rotting peanuts; twigs are thick and have heart-or shield shaped scars.
HARM: Tree-of-heaven can grow and spread very quickly, outcompeting native plant species for sunlight and space. It also produces a toxin which inhibits the growth of other plants. It is also the preferred host for the highly invasive Spotted Lanternfly. It spreads by seeds and by vigorous resprouting.
CONTROL: Tree-of-heaven is difficult to remove once it is established as it responds to cutting with vigorous resprouting. Pull seedlings and saplings manually. For trees larger than 2 inches in diameter the hack and squirt method can be used in summer or fall.
RESOURCES FOR CONTROLLING:
Callery Pear
Pyrus calleryana
ORIGIN: China, Vietnam
IDENTIFICATION: Callery pear or Bradford pear, the most common culivar, is a medium-sized deciduous tree (up to 50 ‘ tall) with leaves which are alternate, 1 ½ - 3 inches long, dark green, rounded, shiny with wavy, slightly toothed margins. The most recognizable feature is its white flower produced in showy clusters in early spring before there are leaves on the tree. The flower has an unpleasant odor. It also produces a small, round, hard, brown fruit with white specks.
HARM: The trees spread aggressively, via dispersal of their seeds by birds, and invade open spaces along roads, forest edges, and in parks, and displace beneficial native trees. Take a drive along the Interstate in March and you will see hundreds of the white flowering trees alongside the road. The rapid spread of this tree poses a major threat to Virginia’s plant biodiversity.
CONTROL: Do not plant Callery pear or any of cultivars, including the Bradford pear. Seedinglings and saplings can be pulled by hand. If you cut medium to large trees down (i.e., diameter greater than 1 inch), it will produce new sprouts, so it is recommended that stumps be treated with a herbicide to prevent resprouting.
RESOURCES FOR CONTROLLING:
David Morehead, University of Georgia, Bugwood.org
Multiflora Rose
Rosa multiflora
ORIGIN: Japan, Korea, China. In the 1930s the Soil Conservation Service promoted it to prevent soil erosion.
IDENTIFICATION: A perennial, upright arching thorny shrub with compound leaves alternate along the stems (each leaf has 5-11 oval leaflets). In May the bush blooms with white flowers about 1 inch wide. Bright red fruit (rose-hips) develop during the summer and remain through the winter.
HARM: Forms dense thickets which choke out other plant species. Spreads by seed eaten and distributed by birds and mammals, sprouting of new plants from the arching canes. Seeds remain viable in the soil for up to 20 years.
CONTROL: Do not plant. Manually remove with a shovel or grubbing hoe and remove entire root. Large plants can be repeatedly cut back or mowed for several years. Goats can also be used to consume the leaves. Large plants can be cut and treated with an approved herbicide.
RESOURCES FOR CONTROLLING:
