The Best Weed Killer for Spotted Spurge

Spotted spurge is an annual weed that invades lawns and flowerbeds. Gardeners may identify spotted spurge growing in the yard by its dense low-growing characteristics, according to the University of California, Davis, website. It is important to remove the weed from the yard with the correct type of weed killer to prevent harming your grass or ornamental plants.

Pre-emergent herbicide prevents spotted spurge seeds from germinating only when used correctly. Spotted spurge seeds germinate when soil temperatures rise to 55 to 60 degrees Fahrenheit at a depth of 1 inch in the soil, according to the University of California, Davis. Gardeners must apply the pre-emergent spray right before soil temperatures favor seed germination. To check the soil temperatures, press a soil thermometer in the first inch of top soil in the early spring. Check the soil temperatures in the morning and afternoon. Average both temperatures to get an accurate reading.

Apply a pre-emergent herbicide that contains an active ingredient such as pendimethalin, trifluralin, dithiopyr and oryzalin, as recommended by UC Davis. Spray the lawn and garden beds evenly with the herbicide. Make sure to spray areas that do not normally see spotted spurge growth, because weed seeds may have spread. Water the lawn and garden after applying the spray. Without supplying water, the pre-emergent herbicide will not sink into the soil to prevent weed seed germination.

Post-emergent herbicide may be used to control existing spotted spurge weeds. Avoid mowing the lawn for two days before and after applying post-emergent herbicide. The more surface area on the spotted spurge, the more effective the spray will be absorbing into the foliage. Apply a post-emergent spray to your lawn that contains active ingredients such as 2,4-D, MCPP or dicamba. For flowerbeds, gardeners should carefully use a broad-spectrum herbicide.

Broad-spectrum herbicide kills any vegetation that it touches. Therefore, gardeners carefully protect their ornamental plants from the spray by placing pieces of plastic over plants. You can also paint your broad-spectrum herbicide onto the leaves of spotted spurge to remove weeds growing right next to your ornamental plants. For this herbicide type to be effective, spray broad-spectrum spray when there is a 48-hour window of dry weather. Turn off your irrigation systems, so the water doesn't remove the herbicide.