Leafy spurge (Euphorbia esula)

A flowering leafy spurge plant

 
 

Leafy spurge is an herbaceous plant that can grow up to four feet tall. It can cover open grassy areas, decrease native plant species, and reduce forage for grazing animals. Managers have released biological control insects to reduce the abundance of leafy spurge in Minnesota. The appropriate scientific name or names for leafy spurge in the United States are under study, so you may see leafy spurge referred to as Euphorbia esula or Euphorbia virgata on websites and educational materials.

Caution: Leafy spurge sap is a white, milky, latex-like substance that can cause skin irritation in humans and can be toxic to livestock. Wear gloves and cover skin when working with this plant.

Description

Appearance

Leafy spurge is an herbaceous plant that grows two to four feet tall and has flowers that are a distinct yellow/green color. The plant's stems, flowers, and leaves emit a white milky sap when broken.

Leaves and Stem

Leafy spurge leaves have smooth edges, can be up to three inches long, and come off the stem one at time at each leaf node (an alternate pattern). Leaves are shorter and scale-like on the lower part of the stem. Plants have smooth stems.

Flowers

Instead of petals, the small flowers have showy yellow-green bracts that look like modified leaves around the reproductive part of the flower. At the top of the stems, flowers are grouped in umbrella-shaped clusters with seven to ten flowers. Lower on the plant, single flowers grow from leaf axils where the leaves attach to the stem. Flowers open in late May and bloom from June into fall.

Seeds

Seeds disperse explosively from a seed capsule that can send them up to 15 feet away from the parent plant. The seeds have a high germination rate and are viable in the soil for up to ten years.

Roots

Roots can grow 15-30 feet deep and can spread 15 feet to the side. Plants can reproduce vegetatively from crown and root buds.

Biology

Leafy spurge is a perennial plant that grows well in sunny and partly sunny areas such as pastures, grasslands, prairies, and roadsides. It can grow well in a wide range of soil types from dry to moist. Plants can reproduce sexually by seed and spread vegetatively from underground roots.

Origin and Spread

Leafy spurge is native to Europe and Asia. It was introduced to the United States in the late 1800s as a contaminant in oats from Russia. Today, leafy spurge is found in most northern states and throughout Minnesota.

Refer to EDDMapS Distribution Maps for current distribution.

Don't be fooled by these look-alikes

  • Cypress spurge, Euphorbia cyparissias (invasive) – Cypress spurge is shorter than leafy spurge and has thinner leaves.
  • Butter and eggs, Linaria vulgaris (invasive) – Butter and eggs leaves can look similar to leafy spurge leaves. Butter and eggs flowers are very different as they have yellow, snapdragon-like flowers with a long spur while leafy spurge flowers have yellow-green bracts.
  • Flowering spurge, Euphorbia corollata var. corollata (native) – Flowering spurge has white flowers and the leaves on its upper stem are attached in whorls with multiple leaves coming off the same point on the stem.
 
Regulatory Classification

This species is a Minnesota Department of Agriculture Prohibited Noxious Weed on the Control List meaning that efforts must be made to prevent the spread of seeds or other propagating parts. Additionally no transportation, propagation, or sale is allowed.

Threat to Minnesota
  • Leafy spurge is toxic to cattle and horses.
  • Leafy spurge greatly reduces the productivity and biodiversity of pasture and prairie lands.
What you should do

One way that invasive plant seeds and fragments can spread is in soil. Sometimes plants are planted purposefully. You can prevent the spread of invasive plants.

PlayCleanGo: Stop Invasive Species in Your Tracks

  • REMOVE plants, animals & mud from boots, gear, pets & vehicle.
  • CLEAN your gear before entering & leaving the recreation site.
  • STAY on designated roads & trails.
  • PLANT non-invasive species.
Native Substitutes
 
Control Methods

Mechanical control can be done by mowing, but must be repeated throughout the season to cut resprouts. Mowing alone will not eliminate infestations. In some cases, mowing can increase leafy spurge densities. Do not mow if seed is present. Mowing is most effective when done before an herbicide treatment. Similarly, prescribed burning can also be effective when combined with an herbicide treatment.

Grazing using goats or sheep can reduce leafy spurge populations. Contact University of Minnesota Extension for advice related to pasture management. If you move grazing animals off site after grazing, take actions to prevent the animals from moving seeds that may be in fur or hooves. Plan for a period for seeds to clear the animals' digestive systems before moving them to new sites so that animals do not bring leafy spurge seeds to new sites.

Herbicide control can be done by using systemic herbicides that are taken up by plants and move within the plant, which can kill leaves, stems, and roots. Multiple applications over time are likely necessary. The herbicide imazapic (ex. Plateau) can be used for spot treatments in late September thru October when native plants have gone dormant and leafy spurge has a second flush of growth (wear gloves and test to see that the milky sap still seeps from a broken or cut stem). Other herbicide options include 2,4-D and glyphosate.

Biological control is widely used in Minnesota using the leafy spurge beetle Aphthona lacertosa. The larvae of the beetles feed on the plant roots, damaging the plants. For more information about using leafy spurge biocontrol, visit the Minnesota Department of Agriculture leafy spurge biocontrol webpage and contact your local county agricultural inspector. Additional biological control insects for leafy spurge include root-boring beetles, three other root-mining beetles, and shoot-tip gall midges.

Reporting

Report new occurrences by submitting a report through EDDMapS Midwest, emailing Arrest The Pest, calling Arrest the Pest (1-888-545-6684), or contacting your local county agricultural inspector.

Resources