Wild Parsnip, (Pastinaca sativa), is a biennial/perennial herb native to Eurasia. It is noxious and highly invasive. It was introduced to the US in the 1600s.
Wild parsnip is very common throughout North America. Large populations in New York are found in the Lower Hudson Valley, Catskills, and the southern portion of the Adirondacks.
Contact with the plant can lead to serious skin irritation. The plant contains psoralens (chemicals that make skin sensitive to sunlight) which cause burn-like lesions within 24 hours after exposure.
Wild parsnip displaces native plants and forms large monocultures. Below is a photo demonstrating how dense wild parsnip populations can grow.
Leaves resemble the leaves of celery and have two to five sharply toothed paired leaflets that grow along the stem. Stems are yellowish-green in color with vertical grooves (no red/purple blotches or hairs) and can grow up to 5 ft. tall. Flowers resemble Queen Anne’s lace but are a greenish-yellow color. The flat-topped cluster (umbel) can grow 2-6 inches in diameter. Wild parsnip blooms from late June to July. Seeds mature by early July. Plants die after producing seeds. Seeds can remain viable in the soil for up to four years.
Manual or mechanical methods of control are not recommended because they will expose the operator to the plant sap and spread seeds. If you must get near the plants use gloves, protective clothing and eye protection.
Foliar applications of glyphosate work best if applied to the rosette stage in the spring or fall. Keep in mind that glyphosate kills all plants. Keep it away from desirable plants in the area; read and follow the product label instructions completely.
Several years of treatment may be necessary to bring large populations under control. Continue to scout the area for new plants that may develop from latent seeds.
Title photo: Megan Pistolese-SLELO PRISM
Infestation photo: John M. Randall, The Nature Conservancy, Bugwood.org
ID photos: Megan Pistolese-SLELO PRISM, Bruce Ackley, The Ohio State University, Bugwood.org; Leslie J. Mehrhoff, University of Connecticut, Bugwood.org; Leslie J. Mehrhoff, University of Connecticut, Bugwood.org