Leafy spurge
Euphorbia esula (complex)
Spurge family - Euphorbiaceae

Other common name: Faitour's grass
Native range: Eurasia
Entry into the United States: The plant was first reported in the United States in 1827.

• BIOLOGY

• INFESTATIONS

• COMMENTS

• THE PROBLEM

• THE COSTS

BIOLOGY

Life duration/habit: Leafy spurge is an aggressive, persistent, deep-rooted perennial, growing to a height of 1 meter (3 ft) or taller. Vegetative stems manufacture sugars for root reserves while other stems produce flowers.

Reproduction: Leafy spurge reproduces by vegetative re-growth from spreading roots and by the production of large quantities of seeds that are often dispersed by birds, wildlife, humans, and in rivers and streams.

Roots: Leafy spurge roots are brown with pinkish buds. Plants are able to maintain high root reserves through an extensive root system, ranging from a massive network of small lateral roots near the soil surface [within 30.5 cm (12 in)] to deep, penetrating taproots that may extend to depths of 3 to 7 meters (9 to 21 ft). This ability to maintain high root reserves permits the plant to recover quickly from physical and most chemical damage.

Stems and leaves: The stems are thickly clustered and bear narrow, 2.5 to 10 cm (1 to 4 in) long leaves that are alternately arranged along the stems. When damaged, leaves and stems produce a milky latex.

Flowers: The small flowers are yellowish-green, arranged in clusters, and enclosed in yellow-green bracts.

Fruits and seeds: Seeds are oblong, gray to purple, and occur in clusters of three. When dry, the seed capsules shatter, scattering seeds away from the plant.

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INFESTATIONS

Worst infested states: Leafy spurge now extends from southern Canada through the northern United States, and is approaching areas as far south as Texas. (see Leafy Spurge Distribution)

Habitat: It has become dominant on rangelands and pastures in a wide range of environments throughout much of the United States.

Impact: Leafy spurge produces a milky latex that is poisonous to some animals and can cause blistering and irritation on skin. The digestive tract is similarly affected when this plant is eaten by humans and some animals. In cattle it causes scours and weakness. When ingested in larger amounts it can cause death. Cattle usually refuse to eat leafy spurge unless it is given to them in dry, weedy hay or when better forage is not available.

A conservative 1979 estimated loss in the United States of $10.5 million annually was based on expenditures for controlling leafy spurge and loss of productivity. Although leafy spurge infestations are most severe on undisturbed lands, on cultivated cropland the weed can reduce crop yields by 10 to 100%. A 1990 study conducted by North Dakota State University estimated the direct annual financial impact in Montana, North Dakota, South Dakota, and Wyoming to be $40.2 million with secondary impacts at $89 million and the potential loss of 1,433 jobs annually.

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COMMENTS

Leafy spurge is extremely difficult to control by chemical means and almost impossible to control by cultural or physical methods in rangelands. It apparently has the ability to purge undesirable chemicals from the root system in approximately the top 45 cm (18 in) of the soil, allowing the remaining portion of the root system to regenerate as soon as the effect of the chemical in the soil has dissipated. Although leafy spurge causes problems with cattle that consume it, sheep generally can be taught to feed on it and goats will seek it out. Both sheep and goats are utilized in weed control programs to "keep the yellow out" and to retard the spread of leafy spurge. People should handle the plant with caution because the latex can cause irritation, blotching, blisters, and swelling in sensitive individuals. The eyes should never be rubbed until after the hands are thoroughly washed. The dried latex is often very difficult to wash off, consider wearing lightweight latex gloves when handling the plant.

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Why should I be concerned?

The problem

Leafy spurge (Euphorbia esula) is an invasive exotic weed that infests more than five million acres of land in 35 states and the prairie provinces of Canada. (see Leafy Spurge Distribution) It causes significant problems in the northern Great Plains by invading grazing lands for cattle and horses, reducing rangeland productivity and plant diversity, degrading wildlife habitat, displacing sensitive species and drastically reducing land values.

A native of Eurasia, where it is controlled by natural enemies, leafy spurge readily adapts to a variety of situations. It infests, and if not aggressively managed, can dominate landscapes ranging from open prairie and hillsides to riparian areas and lowlands. The deep-rooted and prolific perennial has doubled in acreage every 10 years since the early 1900s, and is expanding beyond its foothold in the western United States.

With a head start of more than 100 years before control efforts were initiated, (see Spurge Timeline) leafy spurge is a tenacious opponent that cannot be eliminated or managed by any single entity or control tool. A collaborative, integrated, area-wide approach is essential to solving this costly weed problem.

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The costs

The economic impact of leafy spurge is staggering. Infestations in the Dakotas, Montana and Wyoming alone are estimated to cost agricultural producers and taxpayers $144 million a year in production losses, control expenses and other impacts to the economy. Every AUM (Animal Unit Month: the amount of grazing required to sustain a cow/calf pair, or six sheep, for one month) lost to leafy spurge infestations costs $167 in lost economic activity. Leafy spurge has literally forced some ranchers out of business.

Its impact, however, cannot be measured in dollars alone. Leafy spurge crowds out native vegetation, resulting in a monoculture that reduces biodiversity and threatens both abundant and sensitive species. The invasion of exotic weed species in national parks, wildlife refuges and other lands set aside for wildlife and recreation has, in fact, reached epidemic proportions. In addition, the most commonly used control tool – herbicides – often have adverse environmental consequences.

In short, leafy spurge is an economic and environmental catastrophe for ranchers, land managers and taxpayers in the U.S. and Canada.