Poison Ivy Perennial; spreads by creeping rootstock; found across U.S. (not AK or CA) and southern Canada, as vine or shrub; flowers in May and June. Entire plant is toxic. Wear protective gloves and clothing. Cut plant at base, let it dry out, and bury or put vines in trash. Do not compost or burn (inhaling smoke can be fatal). Mulch with cardboard.