NOXIOUS WEED ALERT: Leafy Spurge

NOXIOUS WEED ALERT:  Leafy Spurge 

LAKEWOOD, Colo. – The Colorado Department of Agriculture works to stop the spread of noxious weeds across the state through a coordinated effort to detect and eradicate new invaders as well as manage well-established species.  Currently, there are 74 species of plants in the state that are designated “noxious,” meaning they pose a threat to the state’s agricultural productivity, wildlife habitat and native plant communities. 

This month, we feature a noxious weed that colonizes a variety of terrain, including riparian areas, grasslands and mountain slopes:

FACT SHEET & MAP:  www.colorado.gov/ag/leafyspurge

LOCATION:  Leafy spurge is widespread in Larimer, Jefferson, Douglas and Elbert counties, and is scattered elsewhere in smaller populations throughout the state.  The historic spread of this species in the western states is 13-16 percent per year. 

TREATMENT:  The root system of leafy spurge can extend as deep at 30 feet into the soil; therefore, hand-pulling this plant is not a successful option.  Mowing will reduce seed production if repeated every 2 to 4 weeks during the growing season, but will provide little long-term control.  Once the seeds turn brown, they are viable and can produce a new plant. Both sheep and goats can be effective grazers of leafy spurge and flea beetles from the Palisade Insectary are effective especially when combined with grazing and/or herbicides. 

BACKGROUND:  Leafy spurge is one of the earliest plants to emerge in the spring, typically in mid-April to late May. One large leafy spurge plant can produce up to 130,000 seeds. Three-sided seed capsules explode when ripe and project the seeds up to 15 feet away from the parent plant.  Leafy spurge has adapted to a wide variety of habitats in the state and is very competitive with other plant species. Where it becomes established in rangeland, pasture, and riparian sites, it crowds out practically all other vegetation.  The entire plant contains white, milky sap that exudes readily upon stem or leaf breakage. This sap can damage eyes and sensitive skin. 

WHAT YOU CAN DO:  If you see this plant, please contact your county weed management program or CDA.  County weed programs are a tremendous resource for treatment information and management of specific weeds in specific counties.  Find your county contact at www.colorado.gov/ag/coweedcontacts.  You can also email CDA at Steve.Ryder@state.co.us.