Alternate name: Wolf's-milk
Family: Euphorbiaceae, Spurge view all from this family
Description This robust perennial weed with showy yellow-green flowers and toxic milky sap forms large monocultural stands.
Habit: introduced perennial herb; thickly clustered semi-woody stems; massive root system; milky sap.
Height: 8-36 in (20-90 cm) or more.
Leaf: bluish-green, alternate, upright, linear to oblong, 1-3 in (2.5-7.5 cm) long, 0.125-0.3 in (3-8 mm) wide; at top of stem becoming shorter, wider, rounder, whorled at top; at base of stem, scale-like.
Flower: flower-like structure, to 1.5 in (38 mm) wide, with 2 heart-shaped yellow-green bracts, surrounding 4 small crescent-shaped glands and a greenish-yellow center (the actual flowers); in domed terminal cluster of 7-10 flowerheads.
Fruit: small capsule, 0.125 in (3 mm) diameter.
Warning Can be toxic if ingested; known to fatally poison cattle. Contact with plant, especially milky sap, can cause irritation of skin, eyes, and mucous membranes. Sensitivity to a toxin varies with a personís age, weight, physical condition, and individual susceptibility. Children are most vulnerable because of their curiosity and small size. Toxicity can vary in a plant according to season, the plantís different parts, and its stage of growth; and plants can absorb toxic substances, such as herbicides, pesticides, and pollutants from the water, air, and soil.
Flower May to October.
Habitat Almost any open area: grasslands, stream banks, flood plains, shrublands, savannas, open woodlands, dunes, abandoned fields, disturbed or undisturbed sites, roadsides, waste lands.
Range Native to Europe and Asia; introduced throughout the 1800s in ship's ballast and contaminated seed; escaped and naturalized throughout North America; not found in Alaska, most of northern Canada, or the southeast U.S. from North Carolina to Florida to Texas to Oklahoma and Kentucky.
Discussion Also called green spurge, wolf's milk, Faitour's grass. Up to three varieties are proposed. Considered weedy and invasive in most areas; prohibited or noxious in 22 states. Leafy spurge is a particular problem in the Plains states and provinces, where the USDA writes that "...leafy spurge is an economic and environmental catastrophe for ranchers, land managers and taxpayers in the U.S. and Canada."
As in dogwood, the "flower petals" of E. esula are really bracts. The true flowers are 4 tiny yellow dots at the center of the bracts (male flowers) and one green globe on a slim stalk protruding from the center (female flower and fruit). This flower structure, called a cyathium, and the milky juice exuded by the stem, are typical of many Euphorbia species.