Leafy spurge is a persistent, deep-rooted perennial which reproduces by seeds and roots. Leafy spurge has a somewhat woody crown below the soil surface. Each crown area produces several upright stems giving the plant a clump-like appearance. In addition, new stems arise from buds on lateral, secondary roots.
Stem growth starts in April, making leafy spurge an early, vigorous competitor with forage and pasture plants. The plant bears numerous linear-shaped leaves with smooth margins. Leaves have a bluish-green color but turn yellowish or reddish-orange in late summer.
Leafy spurge produces a flat-topped cluster of yellowish-green, petal-like structures called bracts, which bear the true spurge flowers. The showy, yellow bracts appear in May and give the plant a "blooming" appearance. The true spurge flowers, however, develop about 10 days later and have small, green, bracts.