Perennial, deciduous shrub or vine – may stay under 3 feet tall or mature plants may be as high as 13 feet tall. As a vine it grows up tree trunks to heights of 75 feet, sustaining itself with aerial roots. (Poison ivy never acts as a vine.) The poisons in both poison oak and poison ivy are the milky oils found in the phloem layer of the stems, as well as oils and resins in the leaves and berries. Susceptible persons develop a severe, itching, long-lasting skin rash on contact, and severe reactions if smoke from burning poison oak is inhaled.
Extensive stems and extensive root systems exist. Control with systemic herbicides is best accomplished after full foliage is in place. Physical removal may be successful with very young plants with a single stem, and gloves always should be worn when contacting leaves or stems. Burning poison oak should be done with extreme caution, as smoke that is inhaled may cause severe reactions in humans.