Wild parsnip is the weedy Eurasian ancestor of the garden parsnip, a biennial that has naturalized across open habitats in the United States wherever human disturbance has broken the ground. In its first year it produces a rosette of large, compound leaves and concentrates energy into a deep taproot — the only edible part of the plant. In the second year it throws up a tall flowering stem bearing flat-topped clusters of small yellow blooms in the manner characteristic of the carrot family, sets seed prolifically, and dies.

The essential caution with wild parsnip is its chemistry: all parts of the plant contain furocoumarins that cause severe phototoxic burns when plant sap contacts skin in sunlight. Long sleeves, gloves, and long pants are non-negotiable when working near it. Management relies on removing flower and seed heads before they mature to prevent reseeding; herbicides work effectively on basal rosettes. Modern cultivated parsnip varieties are derived from this plant and grown as annuals, inheriting the taproot flavor without the garden aggression.