Poison Ivy and Poison Oak
Les Harrison is the UF/IFAS Wakulla County Extension Director
Despite the heat and bugs, nothing beats spending time outside with family. Make sure children understand the plants to stay away from when they are out picking the abundant wildflowers in bloom this time of year.
The familiar rhymes, “leaflets three, let it be” and, “berries white, run in fright” are good lessons for kids. “Hairy vine, no friend of mine” is another reminder of the physical characteristics of poison ivy and poison oak. Stay safe this summer by knowing how to identify these poisonous plants!
Poison ivy (Toxicodendron radicans) and poison oak (Toxicodendron pubescens) both lurk in wait of unsuspecting victims. Both native plants produce urushiol, a plant oil which will cause a severe skin rash when any part of the plant is contacted.
Allergic reaction occurs by touching the plant, or by coming into contact with the oil on animals, tools, clothes, shoes, or other items which have struck either plant. Even the smoke from burning the plants contains oil particles which can be inhaled, causing lung and airway irritation.
Poison ivy grows in shady or sunny locations throughout the Big Bend region and Florida. It can be a woody shrub up to 6 feet tall or a vine up to 150 feet tall that climbs high on trees, walls, and fences or trails along the ground.
All parts of poison ivy, including the hairy-looking aerial roots, contain urushiol at all times of the year, even when bare of leaves and fruit in winter. Plants are common along old, unmanaged fence rows and the edges of paths and roadways.
Leaf forms are variable among plants, and even among leaves on the same plant; however, the leaves always consist of three leaflets. Leaflets can be two to six inches long and may be toothed, or have smooth edges.
The leaves emerge with a shiny reddish tinge in the spring, and turn a dull green as they age in the summer. They turn shades of bright red or purple in the fall before dropping.
Poison oak is a low-growing, upright shrub which reaches about 3 feet tall. It is found in dry, sunny locations and, unlike poison ivy, does not tolerate heavy shade.
Like its botanical cousin, a single poison oak leaf consists of three leaflets. Distinguishing features included its lobed leaves, which give it the appearance of an oak leaf, and the fine hair covering the leaf stems and leaflets.
Leaflets emerge with a reddish tinge in the spring, turn green, and then turn varying shades of yellow and red in the late fall before dropping.
For more information on identifying poison ivy, poison oak, and other plants containing urushiol, see the EDIS publication,
To learn more about poison ivy and poison oak in Wakulla County, contact the UF/IFAS Wakulla County Extension Office at 850-926-3931 or http://blogs.ifas.ufl.edu/wakullaco/.