Holy Spurge…where did that come from?

Several people have asked me why Leafy Spurge (Euphorbia esula) has made such a big comeback from their efforts to manage the noxious weed. Their concern is justified looking at the amount of spurge that is in the Milk River drainage, from the Phillips County line to Havre.

While this is not a strictly “scientific” explanation, this increase could be simply that leafy spurge has a deep taproot (about 20 feet). In dry years, like 2018 and like this spring, deep-rooted plants do better than shallow-rooted plants. Spurge probably made a gain last year without being noticed. This year it appears to be everywhere!

It is estimated that leafy spurge covers 780,000 acres in Montana according to the 2017 Montana Noxious Weed Management Plan. Conservative estimate would indicate that this size of infestation would increase at the rate of 3% annually or 23,000 acres.

For small patches, Tordon 22K, active ingredient Picloram, is still the best herbicide for control of leafy spurge. Tordon is a restricted use product and there are restrictions on applying it near water. If you don’t have a license, call the Phillips County Extension Office.

For large infestations, anything larger than 40 acres, grazing by small ruminates, mainly sheep because of their affinity for spurge and their herding instinct is the best long-term control tool. You can never get rid of leafy spurge completely but with a plan and continued efforts to minimize or eliminate seed production and patch expansion, you should be able to protect new acres from being infested.

For more information on controlling noxious weeds or to get a color noxious weed book, call or stop by the Phillips County Extension Office.