Swift Current Creek
Invasive Plant Species Control Program

Leafy Spurge
(Euphorbia esula)
Alternate Names:
Wolf's-milk, euphorbia, spurge, faitours-grass

Leafy spurge is native to Eurasia, but was introduced to North America in contaminated seed in the early 1800's. Because it is not native to Canada and takes over landscapes, it is considered an invasive alien species.

It generally grows in pastures, rangelands, waste areas, along roadsides, wooded areas, and riparian areas. It can thrive anywhere from meadows to woodlands because it has a symbiotic relationship with a mycorrhizal fungi that improve its nutrition in dry, nutrient-poor soils.
Interesting Facts:
- Leafy Spurge can begin growing early in the spring, sometimes as soon as the ground thaws. It typically grows 2 to 3.5 ft tall. The actual flowers themselves are very small and yellowish-green in colour, and are surrounded by yellow bracts. These bracts open in late May or early June, while the actual flowers develop sometime after mid-June.

- This plant can regenerate from very small pieces of root, making it very difficult to control and eradicate.

- It can also send its roots down 8 m (26 ft) into the soil! This allows it to tap into nutrients and water that other native plants cannot access. This also allows it to store a lot of resources that it can draw from in order to regrow when the top of the plant is stressed or removed.

- Leafy Spurge rhizomes can extend laterally 15 ft per year from the parent plant! Both the vertical and lateral roots can give rise to shoot buds at almost any point, yet one more way it can spread so fast.
- Leafy Spurge also reproduces by seed production. Each flowering stem produces an average of 140 seeds. A single large plant can produce up to 130,000 seeds!

- The seeds can stay viable (able to germinate) for up to 8 years!

- When a Leafy Spurge plant sets seed, the results are explosive! The seed capsules can shoot seeds 5 m (16 ft) from the parent plant!

- Leafy Spurge seeds float on water, and are easily spread by humans, whether it is via clothing, mud on tires, agricultural implements, or in grain or hay transport.

- This plant produces toxins that can inhibit the germination and growth of other types of plants surrounding it.
- Leafy Spurge plants contain a milky white latex sap, which is believed to be toxic to some animals, such as cattle. However, new research is trying to get cattle to eat spurge. This toxin also irritates skin, and can cause blisters and swelling.

- Leafy Spurge has been documented even in the Yukon Territory!

What Does Leafy Spurge Look Like?
(Click on photos to enlarge)

Photo credit: Team Leafy Spurge

Photo credit: Team Leafy Spurge

Photo credit: Steve Dewey
Utah State University, Bugwood.org

Photo credit: Team Leafy Spurge

Management and Control Options:

Because of its extensive root system, ability to out-compete native plants, prolific seed production, and ability to regenerate from root pieces, Leafy Spurge can be difficult to control, and nearly impossible to eradicate. The following are some methods that can be used to stop the expansion of Leafy Spurge communities and eradicate small numbers of plants.

Biocontrol and Targeted Grazing:

- Grazing by sheep and goats to reduce top growth and eliminate seed production, but does not eliminate Leafy Spurge.

- New research in training cattle to eat Leafy Spurge.

- Grazing should begin in early spring when the spurge reaches about 4 to 6 inches high.

- Leafy Spurge beetles: Generally the most successful in Saskatchewan have been the black dot spurge flea beetle (Aphthona nigriscutis, in hot/dry sites such as slopes or hilltops), the black leafy spurge flea beetle (Aphtohona czwalinae, in moist loam and clay soils) and the brown dot spurge flea beetle (Aphthona cyparissiae, in cooler and moister sites).

- Approximately 3,000 to 5,000 is the recommended number of beetles to release at each infestation site, between the beginning of June and mid-July. Release at multiple points to increase the dispersal, since they are slow to disperse themselves. After 3 to 4 years, beetles may be collected with a sweeping net and taken to new spurge sites. Mark the location of any beetle releases with a GPS or a physical marker (eg. fencepost), and on a map.

- Mowing prior to seed set reduces seed production and will weaken plants, but it is not selective and may harm other plants. It will also not likely reduce the spurge abundance.

Chemical Control:

- Picloram (Tordon 22K), generally applied in the spring or fall, is very effective for controlling Leafy Spurge, and provide up to 85-90% control in the first year after applicaton. However, it is necessary to reapply every four year to see any long-term control, which can be quite expensive.

- Tordon 22K plus 2,4-D applied in the spring annually for approximately 3 years may be a more economical and just as effective solution. This has been shown to have control up to 90-95% after 5 years.

- Tordon 22K cannot be sprayed around water bodies, and is not recommended around riparian areas and wooded areas because it is very slow to break down in the soil. Therefore, it can easily leach into groundwater and can contaminate otherwise clean, healthy water sources.

- Glyphosate and 2,4-D are most commonly used to control Leafy Spurge in wooded and riparian areas. A fall application of glyphosate can provide up to 80-90% control after the first year, with a follow-up spring application of 2,4-D. The 2,4-D is used to reduce top growth and seed production, and prevents new expansion of patches, but does not affect the initial infestation if used alone.

- For best control, herbicides should be applied in the spring just prior to flowering, during seed development and/or in the fall during regrowth. In order for any herbicide to be effective, plans must be made for long-term management and reapplication of herbicides generally every 1 to 3 years, depending on the chemical.

- Control is best achieved if multiple management techniques are implemented together:
-- Mowing, grazing, burning and herbicides can reduce litter on the soil and open the canopy for more light infiltration, which can facilitate better spurge beetle establishment.

- Grazing followed by a fall application of Tordon 22K plus 2,4-D can decrease Leafy Spurge abundance by 98% after the first 3 years and maintain control for 2 seasons after the treatment.

- Mowing, grazing and burning can stimulate new spurge regrowth, and increase the effectiveness of the herbicide for controlling expansion of the infestation.

The key to success in the battle against Leafy Spurge is to monitor the effects of your managment techniques, adjust them as necessary, plan long-term managment and NEVER give up the fight!

Leafy Spurge Beetles for Biocontrol
Swift Current Creek Watershed Stewards have been working with local landowners that have Spurge infestations to release Leafy Spurge Beetles as part of a biocontrol measure. Partnering with other watershed groups and associations, beetles are collected and then released in sites pre-determined by landowners.

The Brown or Black Beetle is used as a means of controlling Spurge from further spread in an area. The beetles feed exclusivley on Spurge; the adults feeding on foliage in the sun and the larvae feeding from within the stem. These beetles,used in conjunction with other control measures, can help keep Spurge stands under control and are a good solution for hard to get to areas such as in steep coulee valleys. Results from the beetles may not be seen right away, but if a population establishes and thrives they can help limit the spread of Spurge to other surrounding areas.
Pictured above are the releasing of Leafy Spurge Beetles on on infested site
Copyright © Swift Current Creek Watershed Stewards 2019

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