The scientific name of the plant is Toxicodendron radicans. Knowing the old rhyme of “Leaves of three, let it be” may be the easiest way to tell if it might be poison ivy, but you need more information to be positive. These photos will allow you to identify the plant, both with and without leaves and at various stages of maturity. While the leaves are the most toxic part of the plant, contact with any part (even when the plant is bare of foliage) can be toxic to you. Even if your cat or dog comes in contact with the plant, the animal can spread it to you. That is why it is essential to learn how to tell what poison ivy looks like throughout the growing season and beyond. This leaf close-up shows plants less than a foot high but already put on their green summer color.
Where Poison Ivy Grows
Poison ivy is native to the eastern United States and eastern Canada; therefore, by definition, it can’t be considered invasive there, even though it spreads aggressively even in that region. But it could be invasive in regions to which it has been introduced. Poison ivy is not fussy about sun and soil conditions, which is one reason why it is such a successful weed. Virginia creeper (Parthenocissus quinquefolia) is commonly mistaken for poison ivy since it’s another vine that often grows in the same places. The difference between Virginia creeper and poison ivy is that it often grows in groupings of five leaflets. Similarly, both plants have a reddish center where the leaflets join. Also, Virginia creeper vines are much less hairy than poison ivy vines. At first glance, box elder (Acer negundo) seedlings grow as three leaflets, which can look like poison ivy. The significant difference is box elder leaves, however, are arranged opposite each other, not alternating like poison ivy.
How to Identify Poison Ivy
Rootlets are why trees, tree stumps, and stone walls are covered in vines. Rootlets can cling to surfaces, allowing the vines to climb. When poison ivy has been climbing a tree for a long time, the vine can become so embedded into its bark that it essentially disappears, with only the rootlets visible. When working around poison ivy, it’s essential to wear gloves (wash the gloves and your clothes separately afterward from your other laundry) so that any residue you came in contact with isn’t transmitted to your food, face, pets, other people, or any other surfaces.
Identifying Poison Ivy vs. Poison Oak vs. Poison Sumac
Poison ivy and poison oak are more alike than poison sumac. They each look like they have three leaves per stem. Each leaf (or, in this case, leaflet) is 2 to 8 inches long and 1 to 5 inches wide. They have teeth along the edges of the leaf. The difference with poison oak is the teeth appear rounded, more like a rounded or bulbous common oak leaf; meanwhile, poison ivy teeth edges appear more pointy. Also, for poison ivy and oak, the juncture where the leaflet joins at the stem is often reddish. The growth habits of poison ivy and oak are different. Poison ivy grows like a vine along the ground or up the sides of trees or structures. Poison oak grows like a shrub with leaves atop longer, upright stems. Like poison oak, poison sumac grows like a shrub or small tree. It can grow up to 20 feet tall and is often found in wooded, swampy locations. A similarity poison sumac has to poison ivy or oak is its stems are red—more than poison ivy and oak. Also, they all produce white berries. Beyond that, poison sumac leaves look very different. Each leaflet is oblong with sharp, pointed tips and smooth edges. The leaflets do not group in threes. Instead, you can expect to see seven to 15 leaflets lined up in pairs; each leaf is about 2 to 4 inches long and 3⁄4 to 2 inches wide.
