Dog-strangling Vine
(Vincetoxicum rossicum)
Overview
European swallow-wort, most commonly know as dog-strangling vine, is a member of the milkweed family. It is native to Eastern Europe, having arrived in Canada with European settlers approximately 120 years ago. It has become established throughout many parts of southern Ontario and continues to spread at an alarming rate. Its prolific seeds are small and have a feathery parachute attached, making them easily dispersed by the wind and able to travel great distances.
Dog-strangling Vine can be found in a range of habitats, including old fields, shrub thickets, Great Lakes coasts, forests, tallgrass prairies and alvars. While DSV generally has reduced vigour and reproductive potential in forests, it can invade closed-canopy forests and it may dominate groundcover, particularly where there are gaps in the canopy.
Main Threats
Like many invasive species, DSV can form dense monocultures, outcompeting native plant species and reducing habitat for insects, birds, and mammals. It can also invade and dominate the understory of mature forests, affecting forest regeneration. Other impacts include invading agricultural fields and pasture lands, and impacting recreational trails by growing dense mats of vegetation.
Alvars, the Bruce Peninsula, and Dog-strangling Vine
Alvars are globally rare habitats that, at a small scale, can be among the most species-rich communities in the world. In North America, almost 75 percent of these alvars are located in Ontario, with many found on the Bruce Peninsula. Alvars are especially susceptible to invasions of dog-strangling vine. At some sites, dog-strangling vine has overrun open alvar habitats, displacing plant species and the wildlife associated with them. Given the threat that dog-strangling vine poses to alvar habitats, controlling the spread of this invasive species on the Bruce Peninsula of extreme importance. Learn more about alvars here.
Identification
Photo: Jennifer Gibb
Leaves & Seed Pods
Dog-strangling Vine leaves resemble milkweed leaves as they are oval-shaped and arranged oppositely on the plant stem, but are darker in colour and smaller in size.
As early as June, Dog Strangling Vine produces distinct seed pods that are long, slender, and yellow-green in colour. Similar to milkweed, the seeds are attached to feathery tufts of hair, making them easily dispersed by the wind and able to travel great distances
Photo: Nature Conservancy of Canada
Flowers
Dog Strangling Vine produces small, pinkish flowers which bloom from late May to mid-July. These flowers are star-shaped and have five petals about five to nine millimeters long.
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