Leafy Spurge

Euphorbia virgata

Class A Noxious Weed

This plant is new to the state and has been designated a Class A Noxious Weed by the New Mexico Department of Agriculture.

Wildlife & Ecosystems

This plant is detrimental to native ecosystems, negatively impacting the quality of forage for wildlife and reducing biodiversity in plant communities.
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Agricultural Threat

This plant threatens our state's food security and economy by reducing agriculture yields and/or degrading soil resources.
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Livestock Hazard

This plant presents a threat to the health and/or quality of livestock.
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QUICK FACTS

Leafy spurge is an aggressive, noxious weed that thrives in a wide variety of environments, quickly spreading through deep, woody roots and prolific seed dispersal. It competes with native plants, leading to monocultures and ecosystem disruption.
Due to its resistance to herbicides and ability to regenerate from small root fragments, leafy spurge is a challenging pest to manage. It requires a combination of control methods, including herbicide, mowing, tilling, and biological control, for effective suppression.
Leafy spurge causes significant economic losses in agriculture and disrupts ecosystems by outcompeting native flora, reducing forage for livestock, and altering biodiversity. Its toxic sap also poses a health risk to both humans and animals.

1. Overview

family	Euphorbiaceae – spurges	origin	Eurasia
life cycle	Perennial	other names	Flowering spurge, Wolf’s milk, Faitours-grass, Tithymal

Meet leafy spurge, the explosive (literally) weed that is as adaptive as it is persistent, infiltrating landscapes with ruthless efficiency, establishing dense monocultures, and leaving economic ruin in its wake.

Leafy spurge is a highly invasive and noxious weed that poses a significant threat to native plant species, cattle, and agricultural lands. Known for its rapid spread and resilience to many control methods, this weed can quickly dominate pastures, grasslands, and disturbed areas. Leafy spurge competes aggressively for resources, overwhelming more desirable vegetation and altering ecosystems. Its ability to thrive in diverse environments, coupled with its resistance to herbicides, makes it a formidable challenge to land management efforts.

History of Leafy Spurge

Leafy spurge is native to Eurasia and has adapted to many growing conditions ranging from riparian zones to steep, dry slopes. The weed was brought to North America in 1829 as an ornamental or possibly as a seed crop contaminant. It quickly escaped, and by the 1970s, it had invaded most of the northern states and southern Canadian provinces. Today, it has reached the southwest U.S., is present in 36 states, and is widespread across Canada. [1,2,3]

2. ID Guide

What does it look like?

This blue-green weed can grow up to 3 feet tall. The plant produces hairless, erect stems that branch at the top and produce a milky white sap (latex). An easily identifiable characteristic of leafy spurge is the presence of light-green flowers surrounded by heart-shaped yellow bracts, which would make one believe the flowers themselves are yellow. Leafy spurge is similar in appearance to cypress spurge (Euphorbia cyparissias), but is generally larger and produces fewer leaves. [1,2,6]

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Key Features

Roots: The roots are deep and woody, with vertical taproots that can form buds that create new plants near the soil surface. It has creeping roots that form root buds and generate new plants, which also causes continuous grazing or mowing to be ineffective because the roots can store a large amount of energy. [1,2]
Leaves: The smooth, hairless leaves are simple, the leaf blade is entire, and the arrangement is alternate, though leaves and bracts may be whorled or opposite under the flowering branches. The leaves are narrow and oblong. [1,2]
Flowers: The inflorescences form umbrella-like flower clusters at the stem tips. The flowers do not have petals but rather two yellow-green bracts, which form a cup shape and are often mistaken for petals. [1,2]
Seeds: The flowers produce seed capsules with three chambers, each containing seeds ranging from yellow-brown to gray. Once mature, the capsules burst open and disperse seeds up to 15 feet away from the parent plant. [1,2]

Jan Doležal, inaturalist.org

Flowers form umbrella-like clusters at the stem tips. The flowers do not have petals but rather two yellow-green bracts.

B.Byambajav, inaturalist.org

Most seeds germinate in early spring, but germination may occur throughout the growing season.

Steve Dewey, Utah State University, Bugwood.org

The roots are deep and woody, with vertical taproots that can form buds that create new plants near the soil surface.

alcesevropsky, inaturalist.org

The smooth, hairless leaves are simple, narrow, and oblong.

Gerrit Öhm, inaturalist.org

The plant produces hairless, erect stems that branch at the top and grow up to 3 feet tall.

Julia Scher, USDA APHIS PPQ, Bugwood.org

The flowers produce seed capsules with three chambers, each containing seeds ranging from yellow-brown to gray.

3. Infestation Basics

“Leafy spurge has unique physiological characteristics which make it difficult to control; it can rejuvenate itself from extensive root reserves and sustain itself against repeated attacks.”

-Dean A. Bangsund, Et al., 1998

Impacts

Where does it grow, and how does it spread?

Leafy spurge thrives in various soil types, particularly after a disturbance. It is often found in pastures, waste areas, roadsides, sandy river banks, floodplains, and grasslands. The seeds float and can travel great distances via waterways. [1,2,6]

In the western states, Leafy Spurge grows at elevations ranging from 4,600 to 9,500 feet (5,000-6,000 feet in New Mexico). It thrives in semi-arid climates and can grow in a wide range of soils, from rich, moist riparian soils to dry, nutrient-poor rangeland soils. Infestations tend to increase as soil textures shift from clay to sand. Seedling emergence and survival are generally ideal in fine-textured soils. Greenhouse studies suggest that when soil nitrogen levels are high, Leafy Spurge may exhibit lower root biomass, with roots concentrated in the upper soil layers. [6]

Most seeds germinate in early spring, but germination may occur throughout the growing season. Seeds can remain viable for 8 years or more in the field. These species primarily propagate new infestations from seeds, but Leafy Spurge can also expand vegetatively by producing buds from roots or by utilizing root fragments as small as 0.5 inches. Seed production will usually be completed by mid-August in northern climates. [1,4]

Seed dormancy may be broken at any time, and germination can occur in a wide range of temperatures. Each flowering plant stem can produce over 200 seeds. In early spring, before the last frost, the plant may reproduce from buds on the apex of the root crown and stem. Seedlings can appear purplish-red, and most will appear from late May to early June. [1,4]

Once the seed pods reach maturity, the capsules burst open, ejecting the seeds as far as 15 feet from the parent plant. These seeds are equipped with elaiosomes, which are fleshy attachments that help attract ants for further dispersal. [5]

Key takeaway: Leafy Spurge thrives in pastures, waste areas, roadsides, and floodplains. To prevent its spread, it is important to manage soil disturbances and control seed dispersal.

Why is it so invasive?

Leafy spurge persists through a prolific and expansive root system. A unique seed adaptation allows the plant to quickly produce new seedlings with little help from outside sources. The plant may exhibit mild allelopathic properties; this, paired with its aggressive growth traits, allows leafy spurge to become the only dominant plant species in an area. [5,6]

Leafy spurge is not rhizomatous but, instead, can regenerate itself through clonal buds along root structures near the soil surface. Roots are large and woody and occupy huge amounts of space below the surface, making their removal extremely difficult. Plant regeneration from roots can grow very quickly, occupying up to an 11-foot radius in just one year. Seeds spread quickly on their own via exploding seed pods, or they can hitch rides on streams, muddy tires, and feet, or in the hair of passing animals. In 1997, leafy spurge had infested over 2.7 million acres of land in the US Great Plains and Canadian prairie provinces. [1,5,6]

This weed mainly affects the quality of rangelands by outcompeting native grasses and forage. Cattle and horses will avoid the plant itself but may consume it if no other forage is available, leading to health complications.

Key takeaway: Leafy spurge thrives through a combination of expansive root systems, rapid seed production, and the ability to regenerate quickly, allowing it to dominate landscapes and outcompete native species with alarming efficiency.

Common risk factors for invasion

Areas of neglect: While it often pops up in disturbed areas, leafy spurge can also infest undisturbed areas. The weed can often be established in overlooked or abandoned places, such as roadsides, waste areas, and large rangelands. These undisturbed spaces give it the time and opportunity to spread without competition or control. Regular monitoring and weed management in such areas can mitigate this risk.
Site dryness: leafy spurge spreads quickly on drought-prone, dry, or sandy sites. It tends to outcompete other plants more easily during droughts.
Proximity to burned areas: Postfire sprouting is a common occurrence for mature leafy spurge, often resulting in greater abundance on burned sites. This is likely due to the reduction of competing native species. However, the impact of fire on leafy spurge seeds and seedlings is more variable. For instance, a study in western North Dakota’s Little Missouri National Grassland found reduced germination of leafy spurge seeds after a spring fire. Alternately, two sites in east-central North Dakota experienced high seedling density following spring-prescribed burns. While there was no data on survival past the seedling stage, researchers suggested that fire could be an effective method for depleting the seed bank.
Overgrazing: When livestock are allowed to graze in a single area for too long, they will rip through the existing vegetation and expose the top layer of soil. This creates an opening for leafy spurge, but this risk can be mitigated by practices that move cattle around more frequently, such as rotational grazing.
Riparian Areas: Seeds are easily carried by streams and may be subsequently deposited on river terraces and stream banks. While it prefers dry areas, it will tolerate riparian zones, particularly when sandy soil is present.

Economic

This weed will become a monoculture through aggressive seed production and vegetative growth. Aside from big game, it can reduce available forage for domestic livestock and, in rare cases, cause harm to cattle. In 1994, Economic losses in North Dakota from leafy spurge invasion of rangelands and subsequent management costs totaled $14.4 million annually. [1,6]

Ecosystem Health

Once established, leafy spurge displaces native plants, resulting in a notable loss of floral and faunal biodiversity. This significantly reduces forage availability for game, particularly during the winter months, and may even alter migratory patterns. The plant is particularly aggressive in native ungrazed grasslands, making it a severe danger to large acreage ranches. Its dense litter and foliage crowd out desirable forbs and grasses. Some studies have shown that leafy spurge may be allelopathic in nature, but more research is required. The high reproductive and dispersal rates of leafy spurge combined with its tendency to create large, well-established stands make it a severe threat to native ecosystems. [5,6]

Health and Safety

Spurge plants contain a highly irritating latex sap that can lead to skin rashes when exposed to sunlight. It is crucial to wash your hands thoroughly before touching your face or eyes, as the sap can cause significant irritation. Moreover, prolonged handling of this sap is considered potentially carcinogenic. While the entire plant contains this latex, the concentration is highest in the roots. Large quantities of the sap can have a slowing effect on the heart and may even be fatal to humans. [7]

Livestock

Domestic sheep and goats are known to graze on leafy spurge without reservation. In contrast, cows and horses tend to avoid these plants, which causes them to focus on other available plants, further reducing the weed’s competition. The weed’s milky latex causes severe diarrhea when ingested by cows and horses. Exposure to weed-infested grounds by horses can cause blistering and hair loss around the hooves. The risk of this is more significant in areas freshly mowed. [6]

4. Management Strategies

The high genetic variability of leafy spurge makes it a particularly difficult weed to control, as management efforts must be consistently adapted to keep up with changes in the plant’s biology. Because of this, the plant is extremely resistant to pesticides as well as other control measures. Prevention of leafy spurge should be the highest priority before the weed can gain a foothold. If you are at risk of a leafy spurge infestation, always make sure to use certified weed-free seed and hay. After being moved from an infested area, cattle should be quarantined for 6 days and sheep for 11 so they may discharge any consumed seeds. [1,6]

Sheep and goats can be used as a control measure against leafy spurge, though this will likely not eradicate the plant but only suppress it for as long as grazing pressure allows. Frequent tilling has proven successful if a consistent cultivation schedule is upheld. This mechanical method of control should be repeated for 1-2 growing seasons. [1]

DO’s

Select herbicides that are effective on leafy spurge. Apply them in the correct season, typically when the plant is actively growing, for the best results.
Address smaller, early infestations of leafy spurge before they become large-scale problems. This can be more cost-effective and easier to manage.
Combine herbicides with other methods like mowing, tilling, and biological control (e.g., releasing flea beetles) to reduce the spread and impact of leafy spurge over time.

DON’Ts

Avoid spraying herbicides during windy or rainy weather, as this can cause drift or runoff, which reduces the herbicide’s effectiveness and can damage non-target plants.
Move soil or plant material from infested areas: To prevent spreading leafy spurge to new places, avoid moving soil, hay, or plant material from infested areas to uninfested ones.
Rely on a single control method, such as herbicide application, without a complementary approach like mowing or biological control, as this can result in the plant’s resistance or ineffective management.

** The following information is provided courtesy of the UC Weed Research and Information Center. The Taos Soil and Water Conservation District does not endorse the use of any particular product, brand, or application thereof. **

Managing Leafy Spurge without chemicals involves repeated mowing or grazing with sheep or goats to weaken the plant and prevent seed production. Additionally, introducing biological control agents like flea beetles can help reduce infestations over time by targeting the plant’s root system.

Hand-pulling	Hoeing, grubbing, or hand pulling before seed production may be used for small patches. These control methods must be repeated several times over the growing season (2 to 3 week intervals), and for several years. Use gloves when handling leafy spurge due to the irritating effects of the latex.
Mowing	Mowing is generally not very effective for reducing perennial spurge infestations. However, mowing every 2 to 4 weeks can reduce seed production. Mowing may result in more uniform regrowth, which is more conducive to uniform and effective herbicide applications.
Tilling	Two cultivations in fall to a depth of at least 4 inches will help reduce infestations. (A single cultivation may only spread sprouting root fragments.) This should be conducted for 2 to 3 years. Cultivation twice each fall for 3 consecutive years completely controlled leafy spurge in North Dakota. In other habitats, heavy cultivation every 2 weeks during the growing season and every 3 weeks during the late summer and fall for 2 or more years will reduce top growth and regenerating buds, and eventually stress the root system. Clean equipment after cultivating to avoid transporting root fragments.

Spurges are toxic to cattle and horses, but goats and sheep have been successfully used in control programs. Graze in spring when spurges emerge. Stock sheep at 3 to 6 head/acre month, or Angora goats at 12 to 16 head/acre month. These animals will not eradicate perennial spurges but can reduce the seedbank and allow grasses to become established. Animals should be held in a pen for 3 to 5 days before moving to a new area to prevent seed dispersal. Avoid overgrazing and excessive disturbance in pastures and rangelands, and reduce cattle stocking rates in areas of known infestations. An integrated strategy of early grazing followed by herbicide application to fall regrowth has proven more effective than either strategy alone.

Burning does not significantly affect roots and typically stimulates the production of new shoots from root buds. Burning before release of biocontrol insects can help these insects to become established. Burning does not appear to harm biocontrol populations once established.

Fifteen non-indigenous insect species have been approved for release in the United States for the control of leafy spurge. Five flea beetles (Aphthona spp.) have been established in the Great Plains and Pacific Northwest. Aphthona nigriscutis and A. czwalinae/lacertosa impact the plant by ovipositing eggs at the base of the plant; the larvae feed on the roots, increasing plant morbidity, reducing plant health and creating pathways for the introduction of plant pathogens. Several moths (Chamaesphecia spp. and Hyles euphorbiae) and a stem-boring beetle (Obera erythrocephala) also are being tested. Aphthona spp. flea beetles have produced the greatest impact on leafy spurge, reducing stem densities by as much as 80 to 90% over large areas. This has not occurred in all areas. It is hoped that Aphthona spp. and other insects may eventually provide long term leafy spurge suppression over much of the western United States.

The following specific use information is based on published papers and reports by researchers and land managers. Other trade names may be available, and other compounds also are labeled for this weed. Directions for use may vary between brands; see label before use. Herbicides are listed by mode of action and then alphabetically. The order of herbicide listing is not reflective of the order of efficacy or preference.

2,4-D

Several names

Rate: 1 to 6 qt product/acre (0.95 to 5.7 lb a.e./acre)

Timing: Postemergence at flowering in early summer, or on fall regrowth.

Remarks: 2,4-D is broadleaf-selective and has no soil activity. It can prevent seed formation but does not provide complete kill and will require multiple treatments. One qt product/acre will suppress seed production, 6 qt will control shoots. Do not apply when outside temperatures exceed 80°F.

Aminocyclopyrachlor + chlorsulfuron

Perspective

Rate: 4.75 to 8 oz product/acre

Timing: Postemergence in spring up to flowering, or in fall rosette stage.

Remarks: Perspective provides broad-spectrum control of many broadleaf species. Although generally safe to grasses, it may suppress or injure certain annual and perennial grass species. Do not treat in the root zone of desirable trees and shrubs. Do not apply more than 11 oz product/acre per year. At this high rate, cool-season grasses will be damaged, including bluebunch wheatgrass. Not yet labeled for grazing lands. Add an adjuvant to the spray solution. This product is not approved for use in California and some counties of Colorado (San Luis Valley).

Dicamba

Banvel, Clarity

Rate: 1 to 2 qt product/acre (1 to 2 lb a.e./acre)

Timing: Postemergence in spring to early summer.

Remarks: Dicamba is a broadleaf-selective herbicide often combined with other active ingredients. May require 3 consecutive years of treatment.

Dicamba + 2,4-D amine

Rate: 1 qt/acre each product

Timing: Postemergence in spring at flower emergence and/or to fall regrowth.

Remarks: Add non-ionic surfactant at 0.25%. Do not apply when outside temperatures will exceed 80°F.

Fluroxypyr

Vista XRT

Rate: 22 oz product/acre (7.7oz a.e./acre)

Timing: Postemergence when weeds are small and rapidly growing.

Remarks: This rate provides only suppression of leafy spurge.

Picloram

Tordon 22K

Rate: 1 to 2 qt product/acre (0.5 to 1 lb a.e./acre)

Timing: Applications postemergence at true flower stage are most effective but it can also be applied in fall. The 1 qt product/acre rate may need to be applied annually for 3 to 4 years. Tordon 22K at 2 qt/acre can be applied every other year.

Remarks: Picloram is one of the most effective herbicides for this weed. Most broadleaf plants are susceptible, but relatively safe on established grasses. Use non-ionic surfactant at 0.25%. Picloram has a long residual activity and some have reported that it may injure young or germinating grasses. Do not apply near trees. Tordon 22K is a federally restricted use pesticide. Not registered for use in California.

Picloram + 2,4-D

Rate: 1 to 1.5 pt picloram product/acre + 2 to 3 pt 2,4-D product/acre

Timing: Postemergence in spring, at true flowering. Apply for 3 to 5 consecutive years.

Remarks: See picloram, 2,4-D.

Glyphosate

Roundup, Accord XRT II, and others

Rate: 1 pt product (Roundup ProMax)/acre (0.56 lb a.e./acre) applied three times in a growing season, or 2 pt product (Roundup ProMax)/acre (1.1 lb a.e./acre) applied twice in a growing season

Timing: Postemergence in split applications (June, July, August at low rate, or June and July at high rate), or apply a high rate in fall followed by spring treatment with glyphosate or 2,4-D.

Remarks: Glyphosate is a nonselective herbicide. It has no soil activity. Its effectiveness is increased by addition of ammonium sulfate. Glyphosate is more effective when coupled with revegetation with competitive perennial grasses.

Glyphosate + 2,4-D

Rate: 1 pt glyphosate product /acre + 1.5 pt/acre of 2,4-D product (glyphosate at 6 oz a.e./acre + 2,4-D at 11 oz a.e./acre)

Timing: Postemergence in late spring just before seed set.

Remarks: This tank mix appears to provide synergistic control. Treatment should be repeated for 3 years. See remarks for glyphosate, 2,4-D.

Imazapic

Plateau

Rate: 8 to 12 oz product/acre (2 to 3 oz a.e./acre)

Timing: Preemergence or early postemergence in fall when plants begin to grow but before hard freeze. More than one treatment will likely be necessary.

Remarks: Imazapic has mixed selectivity and some soil residual activity. It tends to favor members of the Asteraceae and some grasses. Use a methylated seed oil surfactant at 0.25%. Not registered for use in California.

Imazapyr

Arsenal, Habitat, Stalker, Chopper, Polaris

Rate: 1 to 1.5 pt product/acre (4 to 6 oz a.e./acre)

Timing: Postemergence at flowering.

Remarks: Imazapyr has a long residual activity and leaves more bare ground than other treatments, even a year after application. It is nonselective.

Other products

Quinclorac (Paramount) is extremely selective from 8 to16 oz product/acre applied in spring at flowering. Overdrive in combination with the low rate of quinclorac is also effective.

5. Citations

[1] Sheley, Roger L., and Janet K. Petroff. Biology and Management of Noxious Rangeland Weeds. Oregon State University Press, 1999.

[2] Clyde Franklin Reed, and the United States Agricultural Research Service. Common Weeds of the United States. New York, Dover Publications, 1971.

[3] USDA. “Euphorbia Esula L.” Usda.gov, 2025, plants.usda.gov/plant-profile/EUES. Accessed 4 Feb. 2025.

[4] Goodwin, Kim, Et al. “Leafy Spurge: Biology, Ecology and Management.” Apps.msuextension.org, Jan. 2003, apps.msuextension.org/publications/pub.html?sku=EB0134.

[5] UDSA, NRCS. “Leafy Spurge Plant Guide.” https://plants.usda.gov/DocumentLibrary/plantguide/pdf/pg_eues.pdf. Accessed 7 Feb. 2025

[6] USFS. “Euphorbia Esula.” Www.fs.usda.gov, www.fs.usda.gov/database/feis/plants/forb/eupesu/all.html. Accessed 7 Feb. 2025.

[7] Elpel, Thomas J., and Pamela G. Sherman. “Leafy Spurge.” Wildflowers-And-Weeds.com, 2024, www.wildflowers-and-weeds.com/weedsinfo/Euphorbia_esula.htm. Accessed 7 Feb. 2025

罗心宇 , inaturalist.org

charlotte_gr, inaturalist.org

Fun Facts

Many beekeepers utilize leafy spurge as an early-season source of food. Honey produced from leafy spurge is bitter but freezes at a lower temperature than honey produced from other botanicals. This makes leafy spurge honey a useful winter food source for bees and is usually fed back to them. [6]

Jennifer Andreas, Washington State University, Bugwood.org

J Mark Earlam, inaturalist.org

Rob Routledge, Sault College, Bugwood.org

Fun Facts

Leafy spurge has a higher protein content than most grasses. Sheep and lambs seem to have a higher weight gain rate when fed leafy spurge. This is an added benefit of using sheep to help control the weed’s spread. [6]