Cow Parsnip, a large, weedy plant of the carrot family. The common cow parsnip of North America grows to a height of nine feet (2.7 m). The leaves are six inches (15 cm) wide and are divided into segments like the fronds of a fern. The cow parsnip has flattopped clusters of tiny, white flowers. It grows best in moist, sunny places. It is sometimes grown in wild-flower gardens. The stems and roots edible.