Leafy spurge
(Euphorbia esula)
Biological Category
Plants
NY Legal Status
Prohibited
Species Type
Other Herbaceous
DESCRIPTION
Leafy spurge is a member of the Spurge family (Euphorbiaceae).
An erect perennial growing to three feet tall, leafy spurge often grows in large clumps due to prolific vegetative growth from an expansive root system. Conspicuous during the growing season due to its yellow-green foliage and flowers, all parts of the stem and leaves exude a milky white sap when damaged.
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Leaves: Leaves are arranged alternately, are simple, lance shaped, and two to six inches long, although at the plant’s stem base, leaves may be reduced in size.
Flowers: Flowers are greatly reduced and lack both sepals and petals. The inflorescences are lime green to yellow in color and contain a single female and 12 to 25 male flowers
Leafy spurge was accidentally introduced as a seed contaminant of grain in the early 1800s. The species is now extant in at least 37 states.
Leafy spurge is tolerant of a variety of soil conditions but competes best on dry sites where competition from native plants is reduced. In the Hudson Valley, the species can be found in waste places such as roadsides, old fields, active pasture land, and woodland edges. Although leafy spurge is more likely to colonize disturbed sites it does not require disturbance to establish. Once the species has a foothold in a new habitat, it is extremely difficult to control.
The insect pollinated flowers of leafy spurge produce approximately 200 to 250 seeds per plant, about 80% of which is viable. Although the seeds can undergo a prolonged period of dormancy, depending upon climatic variables, 99% of seed will germinate in the first two years. Most problematic for management is the species’ ability to spread rapidly via vegetative reproduction. Shoots arise from anywhere along the plant’s often deeply-buried, expansive root system. Seedlings are capable of producing new root buds only seven to ten days after emergence. Vectors include water, birds, mammals, insects and explosive dehiscence.
Leafy spurge is a herbaceous perennial belonging to the Euphorbiaceae family. Capable of rapid vegetative growth this invasive quickly forms monocultures, diminishing diversity and altering composition in the vegetative communities it invades. Furthermore, leafy spurge is toxic, both to other plants and to herbivores. In this way, the species decreases competition from other plants, displaces natives, and destroys rangeland and pasture for agriculture.
Several biological controls are currently being researched and are in active use in North America. The leafy spurge flea beetles have been most successful at providing some measure of control of this noxious invasive, however, several of the eight species released have had problems establishing adequate population levels at release sites.
Pulling / Digging Up: Hand pulling or digging young plants is ineffective unless all of the expansive and often deeply buried root system is extracted.
Mowing
Girdling: Not applicable
Prescribed Fire: Prescribed fire in combination with other management methods, such as the use of biological control agents and two to three applications of herbicide provide some measure of control against leafy spurge. However, the plant’s deeply buried root system endows this species with a high level of fire resistance.
Prescribed Grazing: Although leafy spurge is palatable to both goat and sheep almost a decade of intensive grazing will not eradicate this species. Compounds in the plant’s sap are toxic to cattle and horses.
Soil Tilling: Not advisable. Soil disturbance will encourage root sprouting, unless deep tilling is done several times per season.
Mulching: No information available
Solarization: Not applicable
Hot Foam Spray: No information available
The pesticide application rates and usage herein are recommendations based on research and interviews with land managers. When considering the use of pesticides, it is your responsibility to fully understand the laws, regulations and best practices required to apply pesticides in a responsible manner. At times, the pest you seek to treat may not be on a pesticide label, requiring a 2ee exemption from NYSDEC. Always thoroughly read the label of any pesticide and consult the NYSDEC or a licensed pesticide applicator with questions.
Foliar Spray: A foliar spray of picloram or imazapic, applied as flowers are developing, is the most effective method of control against leafy spurge. Even so, a subsequent application several weeks later will be necessary, along with follow up for at least five years to reach approximately 90% control.
Cut Stump: Not applicable
Basal Bark: Not applicable
Hack-And-Squirt
Stem Injection: Not applicable
Pre-Emergent Spray: No information available
As with any other invasive infestation complex, large stands of leafy spurge are best managed via a combination of mechanical, biological and chemical means. Burning or sequential cutting or grazing followed by targeted foliar spray, the planting of competitive vegetation and the release of biological control agents will give the most complete, and economical control. Managed infestations should be monitored and controlled for at least five years. All managed sites should be surveilled for at least ten years to watch for newly emerged seedlings.
Post-treatment monitoring: Controlled populations should be revisited at least 2-3 times a season for five years.
Leafy spurge can be composted unless the plant has already formed viable seed heads, in which case all plant parts must be bagged and disposed of. All parts of the plant’s root stock can produce new plants and should be thoroughly dried and crushed or discarded in a landfill.
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