Leafy Spurge

Leafy spurge is an herbaceous perennial in the Euphorbiaceae (spurge) family. It produces one or multiple erect stems from the crown that may reach 1 to 3 feet tall. Stems are branched toward the top. Leaves are long and lanceolate, reaching up to 4 inches long; leaves occur alternately on the stem. Leafy spurge flowers from late spring to late summer. Flowers occur in umbles at the end of stems. Flowers are cyathia, a cup-shaped whorl of bracts (false petals) surrounding a cluster of stamen flowers and single pistil flower similar to a poinsettia. Each cyathium has heart-shaped, bright yellow to yellow-green bracts. Leafy spurge has both a taproot and extensive network of rhizomes that may spread up to 35 feet and reach up to 15 feet deep. Seeds are produced in capsules, with 3 seeds per capsule, and seeds are small, gray or brown with a dark line on one side. Seeds are dispersed with explosive force and may be shot up to 20 feet from the parent plant.

All parts of the plant secrete a milky latex. This sap is toxic to humans, most livestock, and wildlife and can irritate skin and eyes causing blindness.

Leafy spurge is native to Eurasia. It was first identified in North America in 1827 and was likely introduced in contaminated soil from ship ballasts. It creates dense infestations by spreading rhizomes and seeds and spreads to new locations by seeds and root fragments. It is found in pastures, roadsides, agricultural crops, disturbed sites, and in landscaping (as a contaminant in rootballs of nursery stock).

Prevention strategies and cultural control strategies should be utilized as much as possible. Ensure that nursery stock is sourced from a dealer that is not contaminated with leafy spurge. Visit nurseries during the growing season and prior to purchase if possible to prevent accidental introduction.

There are several biological control agents available for leafy spurge; however, infestations of leafy spurge in Teton County are not always dense or extensive enough to support viable populations of agents while other agents have not been successful in the climate in Teton County. 

Hand pulling and digging out of the taproot and lateral rhizomes may be effective for removing small patches of leafy spurge, but these must be repeated throughout the growing season. Wear gloves and long sleeves when handling leafy spurge as the latex is irritating and toxic. Mowing at regular, two week intervals can prevent seed production. Intensive grazing with sheep or goats may reduce seed production. Care must be taken to prevent spreading seeds to a new area after grazing. Hold animals in a pen for 3 to 5 days after grazing. Leafy spurge is toxic to cattle and horses.

Larger infestations can be controlled with herbicides. Spring and early summer treatments prior to bloom are effective. Fall treatments after first frost are effective as the herbicides are readily moved into the root system. Read the label before using any herbicide. Contact TCWP if you have any questions about application rates or how to use an herbicide.

• Weed Report: leafy, oblong and carnation spurge. (2013) DiTomaso, J.M., Kyser, G.B., et al. Weed Control in Natural Areas in the Western United States. University of California Weed Research and Information Center.
• Management of Invasive Plants in Wisconsin: Leafy spurge (Euphorbia esula). (2013) Panke, B., deRegnier, R., and Renz, M. University of Wisconsin Cooperative Extension.
• Leafy Spurge: Nebraska Noxious Weed. Nebraska Department of Agriculture and Nebraska Weed Control Association.
• Leafy Spurge. (2013) Beck, K.G. Colorado State University Extension.
• Leafy Spurge (Euphorbia virgata). Washington State Noxious Weed Control Board.