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  Leafy spurge

Home>Plant Species>Weed Species>Leafy spurge

Drawing of leafy spurge Leafy Spurge
Euphorbia esula

question markDid you know?

Leafy spurge can 'shoot' its seeds up to 15 feet!


How did leafy spurge get here?
This aggressive, long lived perennial forb was imported with contaminated seed around 1827 from Eurasia. Leafy spurge was first recorded in Massachusetts, but spread quickly and reached the western U.S. by the early 1900’s.

What are its characteristics?
Leafy spurge produces somewhat woody stems, up to 3 feet tall, with 1 to 4 inch-long leaves. Close-up of leafy spurge flowers and a pen for scale Inconspicuous flowers surrounded by yellow bracts are grouped in clusters at the tops of shoots, or scattered along the stem. Each flower develops a capsule containing 3 seeds. These capsules open explosively when it is hot and capsules are dry, dispersing seed up to 15 feet from the parent plant. Seed may remain viable for 5 to 8 years in the seedbank.

Leafy spurge has extensive rhizomes and roots that send up shoots from deep in the soil. Roots can penetrate as far as 15-30 feet, but most reach about 8 feet below the surface. Vegetative spread is enhanced in coarse-textured soils, and leafy spurge resprouts readily after fires.

Picture showing sap coming from a cut leafy spurge stemLeafy spurge produces milky sap that irritates the mouth and digestive tract of cattle and some wildlife, though it is palatable to goats and sheep. This sap can cause a rash or blistering in humans. It is suspected that leafy spurge also produces allelopathic chemicals.

Why is leafy spurge a problem in the Great Basin?
Leafy spurge is an aggressive invader with stubborn persistence due to its vigorous roots and rhizomes. Leafy spurge plantWith leafy spurge invasion, native plant diversity is reduced. It replaces more valuable livestock and wildlife forage and the milky sap is poisonous to some animals.

How can we fight this weed?
Moths, flies, beetles, and fungi are being use for biological control with some success. Season-long grazing by goats and sheep may help control leafy spurge. Repeated herbicide application is effective against leafy spurge. Multiple treatments are necessary every year for several years, making large infestations expensive to treat. Refer to the Weed Management Handbook on the University of Wyoming Extension website for current application information.

Weed-free feed should be used, and livestock grazing leafy spurge infestations should be held for 7 days before moving them to uninfested areas. Soil and gravel from infested areas should not be transported to other sites.



Images:
-Drawing: USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 2: 473.
-Flower: Steve Schoenig, CAL Photos.
-Sap: Steve Schoenig, CAL Photos.
-Plant: Steve Schoenig, CAL Photos

Text references:
-Plant Conservation Alliance, Alien Plant Working Group. Euphorbia Esula fact sheet. Available: (http://www.nps.gov/plants/alien/fact/eues1.htm, 26 September 2006).
-Simonin, Kevin A. 2000. Euphorbia esula. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: (http://www.fs.fed.us/database/feis/, 27 September 2006).
-USDA, NRCS. 2006. The PLANTS Database (http://plants.usda.gov, 26 September 2006). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
-Whitson, T. D., et.al. 2000. Weeds of the West., 9th ed. Western Society of Weed Science, Newark, CA.