Leafy Spurge

CLICK HERE FOR INTERACTIVE DISTRIBUTION MAP

Description:

LEAFY SPURGE — Euphorbia esula L.

Euphorbiaceae — (Spurge Family)

Leafy Spurge is a perennial, which stands erect up to three feet tall; reproduces by vigorous rootstalks and seed. Leaves are alternate, narrow, one to four inches long. Stems are thickly clustered. Flowers are yellowish-green, small, arranged in numerous small clusters and subtended by paired heart-shaped yellow-green bracts. Roots are brown, containing numerous pink buds which may produce new shoots or roots. The entire plant contains a milky juice, which, if rubbed on the face, can cause blindness, or a rash around the mouth and eyes. Seeds are oblong, grayish to purple, contained in a three-celled capsule, each cell containing a single seed. Capsules explode when dry, often projecting seeds as far as fifteen feet.

Leafy spurge is native to Eurasia and was brought into the United States as a seed impurity about 1827. However, it seems to be a serious problem only in North America where it infests almost two and a half million acres, mostly in Southern Canada and the North central United States. It has been reported to cause severe irritation of the mouth and digestive tract in cattle which may result in death. It is often spread down waterways and in contaminated livestock feed. Leafy Spurge is poisonous to cattle.

Growing in nearly all soil types and habitats, Leafy Spurge is virtually impossible to control without the use of chemicals. An extensive root system containing large nutrient reserves makes leafy spurge extremely difficult to control. With these deep spreading roots often exceeding twenty feet in depth, the plant is able to create new buds from the rootstock – so if it is pulled, mowed, burned or cut up – it will persistently come back. Seeds may be viable in the soil for at least eight years.

Growth Habit: Perennial, erect, up to 3` tall, spreading by seed or creeping roots.

Leaves: Alternate, long, narrow, ¼" wide and 2" long, usually drooping.

Stems: Branched near top, hairless, entire plant contains milky sap.

Flowers: Inconspicuous, surrounded by large heart shaped floral leaves which turn yellow-green near maturity.

Roots: Brown, numerous pink buds, deep spreading, very persistent.

Other: Grows in nearly all soil types and habitats. Seed is thrown to 20` by exploding seed capsule.

(Courtesy of Weeds of the West)

Control Strategies:

Leafy spurge is a weed of rangeland and pastures. Cows and horses don't like it. So, under grazing pressure from those animals it quickly dominates other vegetation. Sheep and goats will eat it and keep it under control. They prefer Leafy spurge to grass. Good grazing management is critical to success regardless of other control methods used.

Biological control is becoming more effective. A number of different biological control agents have been introduced since 1984. One in particular, Aphthona nigriscutis has proven very effective, reducing Leafy spurge ground cover down to less than 10% at many sites in Fremont County. Between five and ten years is needed after insect establishment before real stand reductions can be expected.

Chemical control is the most effective when applied during active growth stages, in the spring prior to seed set and in the fall on regrowth after the weather cools down. Broadleaf herbicides like 2,4-D, Banvel and Tordon have been used to treat Leafy spurge for many years. Moderate rates of 2,4-D, 1 to 2 quarts per acre, will stop Leafy spurge growth for most of the summer and let the grass grow. A fall treatment reduces the stand density for next year. Herbicides at this rate are relatively cheap and will keep the spurge down, but when you stop spraying it returns in just a few years. Leafy spurge is here to stay so it is a question of what you want to grow, leafy spurge or something else.

On rangeland we have two other herbicides that in combination with biological control should provide longer term control. Tordon has been used at 2 to 3 quarts per acre for many years. It is still a good choice in remote areas. But, around house or on land that maybe subdivided in the future, its residual effects and potential to contaminate ground water make it a poor choice for those sites. Plateau is relatively new to the rangeland weed control market. At 10 to 12 ounces per acre, Plateau looks better than Tordon in two ways. There is less damage to other plants and it seems to last longer due to mode of action. Plateau prevents budding of the plant and seems to rather permanently impact the treated plants. They struggle for years trying to grow burning up root reserves until they are dead. Plateau is hard on cool season and irrigated grasses, so you can't use it on irrigated land very well. Timing is also a limiting factor. Plateau must be applied after August 1, but before a hard frost. In Fremont County we can only use it for a few weeks in the fall. There is a limit to how many acres can be treated at that time of year, so as good as Plateau might be, it will always have a limited role in Leafy spurge management.

Fremont County established Special Weed Management Zones for Leafy spurge in 1990 allowing for a 80% cost share on most control programs and if you have irrigated grass pastures, the District will spray them for free. Contact our office for assistance.

To learn more about biological control for Leafy Spurge visit this link.