Vitis riparia

Flora of North America (2016) does not recognize varieties or subspecies of Vitis riparia. Specifically, plants recognized as V. riparia var. syrticola (found on dunes around the Great Lakes, see Catling and Mitrow 2005) were found to be synonymous with V. riparia because the variation in leaf hairiness is continuous rather than distinct (Flora of North America 2016). Additional varieties and subspecies have been recognized in the past, including var. praecox, but none are considered distinct by Flora of North America (2016) and most local floras. Vitis riparia naturally hybridizes with other Vitis species and is thought to be one of the parents of of Vitis x novae-angliae with V. labrusca (Flora of North America 2016, Wen et al. 2018).

Vitis riparia is a woody vine that is native throughout much of North America, ranging from Canada south to Texas and from the Rocky Mountains east to the Atlantic Coast. It has become naturalized in Saskatchewan (Canada) and in Oregon and Washington (United States). Vitis riparia is particularly important to the cultivated grapevine (V. vinifera) because it is one of three North American species that reestablished the European wine industry in the late 1800s, when many vineyards were decimated by the introduced phylloxera pest. To this day,Vitis riparia is still one of the primary sources of rootstock in grape production worldwide. Vitis riparia is a very wide-ranging species that occurs in many different habitats. While it is likely affected by several different threats, Vitis riparia is so widespread that it is considered to be at a very low risk of extinction.

Vitis riparia is one of the most wide-ranging Vitis species in North America. It occurs from Canada south to Texas, and from the Rocky Mountains east to the Atlantic Coast (Flora of North America 2016, Wen et al. 2018). Vitis riparia is considered native in most of its range; however, it is not native and has become naturalized in Saskatchewan, Canada and in Oregon and Washington in the United States (Flora of North America 2016). The range extent was calculated using localities only within the native range.

Vitis riparia is a wide-ranging species that occurs in many different habitats. While this species is likely affected by several different threats, including development and invasive species, there is limited information available to estimate the scope and severity of each threat. There are likely more impacts of threats on the edges of its range, particularly invasive vines. In the drier parts of its range, changes in hydrology are affecting Vitis riparia. Other threats affecting this species include deforestation, cattle grazing along riparian zones, and herbicide drift from agricultural fields. Vitis riparia is also mistakenly removed from areas because it resembles non-native invasive vines, particularly porcelain berry (Ampelopsis glandulosus).