Eastern Poison Ivy (Toxicodendron radicans) vs. Western Poison Ivy (Toxicodendron rydbergii)
Updated June 3rd, 2026These two species are visually similar and have significant range overlap in eastern Canada and the north and central US. Vining plants or ones with aerial rootlets are easily identified as T. radicans, which averages hairier and with slightly larger fruit. T. radicans ranges farther southeast, to lower elevations, and into shadier habitats, and is found in a wide range of moisture conditions and soil pH. T. rydbergii ranges farther west and north, is more restricted to higher elevations and open habitats. In the overlap zone, T. rydbergii prefers rocky, usually acidic soils and drier conditions, although deeper in the arid west it is restricted to richer soil in ravines and canyons.
