Invasive Noxious Weed Alert!
Oblong spurge (Euphorbia oblongata) – listed as an invasive
and noxious weed by the Oregon Department of Agriculture – is a yellow flowered
forb reaching 3’ tall at maturity. Three yellow bracts around the flower with oblong or eggleaf shaped leaves make this invasive distinct from other Euphorbia species.
Benton SWCD is working with grant funds from the
Oregon State Weed Board to monitor and treat 22 sites in Benton County. Five of these sites were just discovered in May, and several of the sites from last year need additional treatment because the weed is so persistent. Landscapers,
contractors and OSU students are serving as eyes for our staff to identify areas, like the one above, that need treatment.
Oblong spurge is easily pulled by hand especially from soft and moist soil conditions – please pull it from your yard and garden! Wear gloves when pulling because the milky sap can be
Two new sites where BSWCD will treat oblong spurge:
Vineyard Mountain has
oak habitat that could be heavily impacted by the spread of oblong spurge. Infestations in this area likely began after planting by a homeowner and it is now spreading well beyond 1,000 feet into other areas where it was not intentionally planted.
More assessment surveys will continue throughout the summer months.
Southtown, near the Corvallis airport is another infestation that was installed by the homeowner, and then discovered by a landscaper who knew to contact BSWCD after being educated about its impact on native plants and wildlife.
Special Request: if you believe that oblong spurge is in your neighborhood or local area, please email Michael
Ahr to discuss the location and, if possible, include a photo so that we can follow-up on potential treatment.
Learn more about Oblong spurge from ODA here.