Dead poison ivy vines and leaves still contain urushiol and can cause a rash even after being dead for several years. For more Better Homes & Gardens news, make sure to sign up for our newsletter!

Poison ivy grows vigorously throughout much of North America. It can grow as a shrub up to about 1.2 m (4 ft) tall, as a groundcover 10-25 cm (4-10 in) high, or as a climbing vine on various supports.

Poison ivy can grow as a low groundcover plant, a small shrub, or a vine. When it vines and climbs trees, the older vines are covered in small, fine, reddish hairs—a dead giveaway.

You do not even have to contact the plant directly, as urushiol oil can get on tools, pets or clothing, ... Urushiol can even persist in dead poison ivy plants and leaves for more than a year, ...

Poison ivy is often mistaken for Virginia creeper (Parthenocissus quinquefolia), another vining woody plant which is also spread widely by birds. Virginia creeper, however, is not poisonous and ...

However, the vines grew even faster, and poison ivy was the speediest of all, growing 70% faster than it did without the extra carbon dioxide. "It was the max.

Like poison ivy, its leaves have a alternate leaf pattern, and can grow as a shrub, bush or vine. In the spring, poison oak's leaves appear shiny with reddish or green colors that can curl inward.