A member of the wood sorrel family, oxalis is a weed commonly found in lawns. This weed can actually be confused with clover when it's not in flower. Here's how you tell them apart: Clover has rounded leaflets in sets of 3, whereas oxalis has heart-shaped leaflets in sets of 3.

There are two types of oxalis: common yellow woodsorrel (Oxalis stricta), which has light green leaves, and creeping woodsorrel (Oxalis corniculata), which has reddish, hairy leaves and spreads by way of its creeping stems.

How to Kill Oxalis

1. Kill oxalis (and other weeds) in hardscapes, landscape beds, and vegetable garden beds with Ortho® GroundClear® Super Weed & Grass Killer. It starts to work right away, but it keeps working to kill weeds at their roots. While it will become rainproof in just 15 minutes, you'll get the best results if you apply on a calm, sunny day. Be sure to read and follow all label directions.
2. To kill oxalis in the lawn, use Ortho® Weed B Gon® Chickweed, Clover & Oxalis Killer For Lawns Ready-To-Spray. It easily connects to your hose and doesn't require any mixing or measuring. For those of you who need to go beyond the reach of a hose, use a tank sprayer to apply Ortho® Weed B Gon® Chickweed, Clover & Oxalis Killer For Lawns Concentrate to take down weeds anywhere in your yard. Don't forget to follow the directions on the label.
3. Fertilizing your lawn regularly (4 times per year) provides the nutrients your lawn needs to grow thick and strong and help crowd out weeds
4. Mowing at a height best for your lawn allows the grass to grow thick and develop a deep root system. If you have a mulching mower, leave the grass clippings on the ground to act as free compost.
5. Your lawn will begin to wilt when water is needed. Whenever possible, take advantage of nature's sprinklers and rely on the rain to water your lawn. If you do have sprinklers, set them so your lawn is watered deeply and infrequently. Most lawns only need an inch of water per week.