Leafy spurge

Leafy spurge

The issue: Leafy spurge

I found leafy spurge (Euphorbia esula) in my yard yesterday. It’s a creeping-spreading perennial from Eurasia that grows to 3 feet tall. It’s most often found on range land, ditch banks, pastures, rights-of-way and perennial crop fields. It tolerates a variety of environments, but does best in dry, sandy conditions. The milky sap is toxic to cattle, horses and many wildlife.

The showy part of the flower head is not the flower, but the yellow bracts. The seeds are ejected up to 15 feet when the seed capsule erupts. New seedlings can take hold in 10 to 12 days.

The bluish-green leaves are 0.25 to 0.5 inches wide and up to 4 inches long, without a petiole.

Leafy spurge has deep roots and rhizomes (underground stems). New plants will often rise from the rhizomes near the surface. Rhizome fragments can generate new plants.

Integrated pest management options:

· Prevention: Feed weed-free hay; keep ditch banks free of seed-producing plants; isolate leafy spurge-fed livestock for seven days before moving to a new area.

· Mechanical: Mowing only reduces seed production; repeated tillage, hand pulling or cultivation every two to three weeks works on small patches.

· Cultural: Thick stands of grass help; manage pastures for good grass health.

· Biological: Several insects are available; spring grazing with sheep or goats helps reduce seed production, don’t overgraze the grasses.

· Chemical: Spring application when the true flowers (not bracts) are present; fall application while there is still milky sap. Be sure the target weed and crop, or landscape situations are listed on the product label. Always read and follow herbicide label directions

It is important to keep leafy spurge from going to seed while employing practices to kill the roots. Combine different IPM techniques as much as possible for several years. A continual monitoring program is essential.

For more information, contact Ron Patterson, University of Idaho Extension Horticulture/Agriculture Educator in Bonneville County, at 208-529-1390 or rpatterson@uidaho.edu.