Sun or shade. Deciduous. Poison ivy can grow as a shrub, a vine, and a trailing groundcover, always with compound “leaves of three” that can be easily recognized with practice. In addition, well-established vines can be identified by the fuzzy, dark brown aerial rootlets they use to climb trees; these can resemble a “hairy” rope. The greenish flowers are insignificant, but the white berries in fall can be distinctive, especially in combination with the spectacular red fall leaf color. The berries are a valuable resource for wildlife in autumn.
All parts of the plant contain urushiol, a clear liquid sap that induces an allergic contact dermatitis in susceptible individuals. The allergy tends to develop and strengthen over time, so although an initial encounter with poison ivy may not result in a rash, continued exposure will eventually induce a reaction. If contact with poison ivy leaves is suspected, rinse skin immediately with cool, running water (or rubbing alcohol, if available) within 15 minutes if possible. (Avoid using hot water, which would open up the skin pores.) Urushiol can also bind to pet hair and gardening tools, and it will remain potent for a long time.
Poison ivy is a member of the Anacardiaceae plant family, along with cashew, mango, and sumac. Poison oak is a close relative, but it grows with a somewhat more shrublike habit; it is not common in Bexar County but can be found around Floresville and La Vernia in Wilson County.Â
Small sprouts can be removed manually with appropriate protection; take care to remove all the rootlets and wash shovels afterwards to remove the oil. Climbing vines may be cut and treated, but they are not typically pulled down to the ground as this would increase the risk of exposure and damage to the tree. Established infestations may require multiple herbicide applications.
Don’t burn poison ivy debris, as the vaporized oil can cause serious lung damage to anyone downwind.Â
Not recommended, but included to assist with identification.Â
