Leafy spurge

Herbaceous perennial with deep root systems and milky sap in stems, flowers and leaves. The liquid is distasteful to some animals and can cause blistering in their mouths or throats. Leafy spurge grows to be 2-3' tall.

Other names for this plant include:

• Common names: spurge, wolf's milk
• Scientific names: E. esula ssp. esula; E. esula var. esula

Classification in Wisconsin: Restricted

Ecological Threat

• It invades open areas, including prairies, savannas and roadsides. It can quickly create monocultures, excluding native vegetation and reducing wildlife habitat value.
• Tolerant of various habitats, from dry to moist and sunny to semi-shade. Most aggressive in areas where soil moisture is limited.

Identification

Leaves: Leaves are simple, alternate, bluish-green, smooth and hairless with pointed tips.

Flowers: Small, yellowish-green, and surrounded by cup-shaped bracts. Flowers are paired, with 7-10 pairs clustered in umbels at the tops of stems. Blooms late spring through mid-summer.

Fruits & seeds: Capsules contain three seeds each and burst when dry, dispersing seeds explosively. Each plant can produce more than 250 seeds. Seeds remain viable in the soil for up to 8 years. Wildlife, humans and water spread them.

Roots: Extensive root system with taproots extending up to 15' deep and lateral roots spreading up to 35'. New sprouts from root buds facilitate spread into undisturbed areas.

Control

Mechanical: Hand pulling or digging is only effective if the entire root system is removed.

Chemical: Aminopyralid is effective for spot treatments. Imazapic with methylated seed oil (MSO) is recommended for fall applications.

Biological: Stem and root boring beetle, four root-mining flea beetles and a shoot-tip gall midge.

For more information on control techniques, visit the Leafy spurge factsheet [exit DNR] by the University of Wisconsin-Extension.

Resources

Sources for content:

• Czarapata, Elizabeth; Invasive Plants of the Upper Midwest: an illustrated guide to their identification and control. The University of Wisconsin Press. 2005.
• Center for Invasive Species and Ecosystem Health, Invasive.org. Last updated on Sunday, March 08, 2009. Leafy spurge [exit DNR]
• Invasive Plant Atlas of New England: Euphorbia esula [exit DNR]
• USDA Forest Service, Southwest Region. Field Guide for Managing Leafy Spurge in the Southwest, 2014. Leafy Spurge [exit DNR]

Links for more information:

• Wisconsin State Herbarium [exit DNR]
• USDA PLANTS Profile [exit DNR]