In grasslands, leafy spurge is an aggressive, noxious weed. Cattle will not eat the weed which is fortunate because the plant contain a toxin that causes scours, weakness, and even death in serious cases. In some places, this plant has invaded entire sections of land, which makes this land worthless.
When trying to control leafy spurge, it can be difficult and costly. If you can, you need to treat smaller patches of this weed before they are able to spread and get out of control. Leafy spurge should be controlled in the fall with herbicides when the plants are growing. Plateau is the best treatment for leafy spurge in grasslands. For treatment, apply 8 ounces of Plateau at least two weeks before killing freeze in the fall and then apply 4 ounces the next spring. By treating for leafy spurge twice, it is very effective and does not injure the native grasses or wildflowers. Another option to control leafy spurge is a tank-mix of Tordon 22k and 2,4-D. This mix is less expensive than the other option, but it doesn't work quite as well.
Do not expect the leafy spurge to be eliminated within one or two years. You need to keep spraying each spring when plants tops of escaped leafy spurge start to turn bright yellow and new seedlings start to appear after a year or two. Reexamine your pasture each spring and control the plants while they are small and easy to kill.
Leafy spurge can ruin your grasslands, but with herbicides, you can keep your pastures from being invaded by this noxious weed.