Tackle the scourge of leafy spurge

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Spurge is a scourge in these parts, but controlling it is the ultimate challenge. A Euphorbia spp., leafy spurge is an attractive plant with clusters of bright yellow/greenish flowers, but don’t let it fool you. With roots that reach 15 feet across and 30 feet deep, it overtakes enormous areas in short order. Plus, with a single plant producing roughly 130,000 seeds, which remain viable for seven years, it is bound to find its way where it doesn’t need to be. Because scourge is so difficult to control, it requires number of tools to try to keep it in check.

Insect control to tackle the scourge

I was hopeful when we saw the attractive spurge hawkmoth, Hyles euphorbiae, caterpillar while hiking near the Missouri River a couple of weeks ago. It’s hard to miss this two-inch long bright orange and black caterpillar with white spots, which are particularly vibrant against the maturing vegetation. These were brought to the United States in the mid-1960s as a potential control for the noxious weed. Although leafy spurge is their preferred food source, they don’t damage the plants enough to make an impact.

A better way to utilize insects in the battle is to incorporate a several types of flea beetles such as Aphthona nigriscutis, A, lacertosa, A. cyparissiae, and A. czwalinae  into the plan. The larvae feed upon root hairs and the adults focus on the leaves. The flea beetles are a good option if you have a small patch you need to control before it grows out of hand or as part of a larger control measure. 

Another reason to get a goat

Sheep and goats are yet another line of defense in the battle of leafy spurge. And I think a dandy reason to bring one (or more) home. Montana State University looked into using the animals on pastures and found it’s a go-to forage for the sheep, and goats eat it regardless of the plant’s stage. 

According to Colorado State University, when they used six to eight sheep per acre for 10 days each July for five years, it reduced the overall leafy spurge infestation by 90 percent. Combine this with the flea beetles and you might not have to use herbicides at all. 

Pulling and spraying

Pulling spurge is difficult because every time you pull a plant, you might leave a piece of a root. We’ve all dealt with plants like this. It’s not easy to eradicate them this way. 

The next option is chemical controls, but this requires the heavy stuff. Think Tordon, dicamba, glyphosate, or 2, 4-D, which are not herbicides to take lightly. Be sure to follow the label carefully. Timing is also important. Spray the leafy spurge roughly two weeks before your first frost. The plants are still actively growing, and at this time of the year, it is more likely to pull the poison into the roots. 

Leafy spurge is pretty, but it’s far too invasive to tolerate in any setting. Truthfully, next to bindweed, this is one of the toughest ones to eradicate. While I wish the beautiful hawkmoth caterpillars took care of the issue, I’d learn more towards bringing in the flea beetles. And it still seems like a terrific reason to bring home a goat!

Meet Amy Grisak

Amy is a freelance author and photographer in Great Falls, MT who specializes in gardening, foods, and sustainable agriculture. She provides information on every kind…

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