Wild parsnip Pastinaca sativa
IDENTIFICATION — This invasive biennial is related to the edible parsnips you may grow in your vegetable garden. Like its cultivated cousin, wild parsnip has a long, white-yellow taproot that is edible.
The first year, a rosette of leaves emerges and grows to about 1 ft. tall. Egg-shaped leaflets are in pairs along the stem and are deeply toothed or lobed. During the second year it sends up a thick, grooved flower stalk. Bright yellow flowers in flat clusters, like dill, appear from May to October. Flowering plants may grow as tall as 5 ft.
FAVORITE CONDITIONS — Wild parsnip spreads by seed and grows just about anywhere in North America in fields, ditches, prairies, bike paths, cultivated gardens and even your lawn. Although it prefers full sun and moist to wet soils, it will grow in shade and dry soils, too.
CONTROL — Hand digging wild parsnip is the most effective control method. But the deep taproot can make it difficult. If possible, identify and dig up plants when they’re in the rosette stage and the tap root is short and easier to dig. Cut or mow flower stalks on mature plants to prevent seeds from forming. Then dig up as much of the plant as you can. Herbicides that contain glyphosate, such as RoundUp®, can be an effective control. Follow label directions. Wear long sleeves, pants and gloves when handling wild parsnip because it exudes a chemical that causes photodermatitis blisters when your skin is exposed to sunlight. These can become very painful and may require medical attention.