Weed of the Month: Wild Parsnip

Wild parsnip

Photo: Virginia Tech Weed ID Guide

Common name: Wild parsnip
Scientific name: Pastinaca sativa L.

Life Cycle: Biennial
Origin: Eurasia
Poisonous: Yes (foliage), skin photosensitivity

Wild parsnip is distributed widely across the United States and Canadian Provinces and frequently grows along fencerows and roadsides. Depending on the location, seeds germinate in the fall or early spring and plants flower from June through July.

Flowers are yellow or yellow with reddish tinge. This erect, growing plant can reach 6 feet in height. The leaves alternate on the stem and are coarsely toothed. Stems are stout and hollow, often with ridges. Roots branch from a tuberous taproot and are edible.

Wild parsnip foliage causes skin photosensitivity and a rash. Humans and horses are sensitive to this species, with reaction severity varying among individuals.

Wild parsnip is a prolific seed producer, and seeds are the only mechanism of reproduction. Mowing, herbicide treatment, or hand weeding should occur well before flower production to prevent seed production. Consult your local Cooperative Extension Service Service personnel for herbicidal control in your area.

William W. Witt, PhD, professor emeritus in the department of plant and soil sciences at the University of Kentucky, provided this information.

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