Japan
"A number of reviews list wisteria flowers, leaves, fruits, and seeds as poisonous, and one further indicates that seed ingestion causes symptoms such as nausea, vomiting, stomach pains, and diarrhea. Japanese wisteria was listed as a minor winter plant food for bobwhite quail in Alabama, and hummingbirds have been observed feeding on the nectar of Chinese wisteria...
Wisterias form dense infestations that spread from horticultural plantings. They tend to establish and spread in forest edges, disturbed areas, and riparian zones, as well as roadsides, ditches, and rights-of-way...
Information regarding the impacts of wisterias on invaded communities includes evidence that both species displace existing vegetation by strangling or shading out native plants and trees. The death of large trees from wisteria establishment results in breaks in closed canopy forest, which favors further growth and spread of wisteria. Once established in an area, wisteria patches can potentially cover several acres; one herbicide experiment in Alabama was conducted in a Chinese wisteria patch that covered 2 to 3 acres (1 ha). The presence of Chinese wisteria was listed as a problem in the restoration of bottomland hardwood forests in Mississippi and threatens old-growth remnant stands of longleaf pine in the Southeast. Chinese wisteria is also listed as occurring on National Wildlife Refuges in Florida.
While both wisteria species are listed as invasive species of concern in a number of states, information as of 2009 suggests that they are less of a perceived threat than other, co-occurring invasive species. For example, in a paper describing woody invaders of eastern forests, Japanese and Chinese wisteria are not considered as much of a threat as other woody vines, including Oriental bittersweet (Celastrus orbiculatus), Japanese honeysuckle (Lonicera japonica), or kudzu (Pueraria montana). However, that status may change in the future." [1]
"As their names imply, Japanese and Chinese wisteria are native to Japan and China, respectively. Chinese wisteria was brought to the United States for horticultural purposes in 1816, while Japanese wisteria was introduced around 1830. Wisterias are used extensively in the southern and mid-Atlantic states to adorn porches, gazebos, walls, gardens and parks, and most infestations in natural areas are the result of plants escaping from such settings." [1]
"As of 2009, there was very little information on the importance of wisteria to wildlife or livestock." [1]
[1] Stone, Katharine R. 2009. Wisteria floribunda, W. sinensis. In: Fire Effects Information System,. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://www.fs.fed.us /database/feis/plants/vine/wisflo/all.html.
