Invasive Plants in Pennsylvania

Chinese and Japanese Wisteria

Wisteria sinensis and Wisteria floribunda

Description: Biology and Spread:

Wisteria are long-lived, Most infestations of exotic deciduous, woody climbing wisterias appear to be the vines that may reach a height result of persistent vegetative of 60 to 70 feet or more. spread of old plantings, Chinese wisteria vines are although seed propagation is brown-gray in color with fine also possible. Four to six white hairs, while the Japanese seeds are contained within wisteria vines are smooth and each fuzzy, flat five-inch-long brown. Both can attain a fruit. diameter of 15 inches or more. The compound leaves alternate along the stem and Photo: Chris Evans, River to River CWMA, www.invasive.org have many leaflets (Japanese: up to 19, Chinese: up to 13). The flowers are showy, violet- Background: blue in color and occur in long drooping clusters. Exotic wisterias are popular ornamental landscape plants that can escape from yards Habitat: into natural areas. They were brought to the U.S. in the early Wisteria prefers full sun, but 1800s. established vines can grow and reproduce in partial shade. It is tolerant of a Range: variety of soil types and moisture levels, but prefers Photo: James Miller & Ted Bodner, Southern Chinese wisteria is more loamy, well-drained soils. Weed Science Society, www.invasive.org widespread than the Japanese Infestations are commonly species, but both can be found found along forest edges, Ecological Threat: throughout much of the east roadsides and rights-of-way. coast, particularly in the south. Because of the twining nature Chinese wisteria can be found of these vines, they can as far north as New England. outcompete trees and other

vegetation for canopy space.

A dense, nearly impenetrable thicket can result, inhibiting

Photo: James Miller, USDA FS, normal forest succession.

www.invasive.org How to Control this Species: Native Alternatives:

A combination of methods Chemical There is a native American yields the best results. wisteria (Wisteria frutescens L For vines climbing up trees Poir.) that grows from Virginia Manual or buildings, cut the stem to Florida. It is not as common and apply a concentrated in the nursery trade as the For small infestations, hand- systemic herbicide like exotics. Other native vine pull, getting the roots too. triclopyr or glyphosate to the alternatives include trumpet Bag and dispose of all plant cut surface of the rooted creeper (Campsis radicans), parts. Any portion of the root portion of the vine. trumpet honeysuckle (Lonicera remaining in the ground may sempervirens) and crossvine re-sprout. For large infestations, a foliar (Bignonia capreolata) - shown herbicide may be the best below. For vines in trees, cut the option, rather than manual stem, pull out the rooted

or mechanical removal portion, and leave the vine in which could disturb too the tree. Do not attempt to much soil. The ideal time to pull it out as it could cause spray is when the plant has damage to the tree or fall and gone dormant in October or injure you. November. Science Society, Bodner, Southern Weed Weed Southern Bodner, www.forestryimages.org

Ted & Miller Photo: James Look-A-Likes: References: American wisteria (shown below) has smaller flower clusters and smooth seed Plant Conservation Alliance’s Least Wanted factsheets: pods. The stems are brown to http://www.nps.gov/plants/alien/fact/wist1.htm reddish-brown and smooth. The vines twine clockwise Invasive Exotic Plant Tutorial for Land Managers: http:// around a tree, whereas the www.dcnr.state.pa.us/forestry/invasivetutorial/wisteria.htm exotics twine counter- clockwise. For More Information:

To learn more about invasive plants in Pennsylvania and the northeast, here are some useful resources:

DCNR Invasive Species Site: http://www.dcnr.state.pa.us/ conservationscience/invasivespecies/index.htm

Plant Invaders of Mid-Atlantic Natural Areas, National Park ern Weed Science Society, Service: http://www.nps.gov/plants/alien/pubs/midatlantic/

Photo: James Miller & Ted Bodner, South- Ted Bodner, & Miller Photo: James midatlantic.pdf