Oxalis, or wood sorrel, is a common weed found in lawns. While young plants can be removed by hand, applying a weed killer ensures the plant is killed down to the root. If you're battling oxalis in your yard, here's how to control it.

What Is Oxalis?

Oxalis, also known as wood sorrel, is a perennial weed that is often mistaken for clover. It is easily distinguished from clover by the 3 heart-shaped leaflets found on top of each long stalk (or petiole) and 5-petaled yellow flowers that bloom from spring through summer. Oxalis can grow to be 4 to 12 inches tall and thrives in full sun or shade. The leaves of wood sorrel fold down at night and open during the day to harvest sunlight. They produce seed capsules that explode when touched, spreading seed in every direction. Oxalis thrives in dry, open places but can also be a problem in moist, well-fed lawns. However, it will most often invade lawns that are thin and weak from improper care.

Types of Oxalis

While there are over 800 different species of oxalis, two are most commonly found in lawns throughout the U.S. Yellow wood sorrel (Oxalis stricta) has pale green leaves, grows in an upright clump, and is most commonly mistaken for clover. Creeping wood sorrel (Oxalis corniculata) has leaves that are covered with with fine hairs and are sometimes tinged reddish-purple. It spreads by stems that creep along the ground, rooting as they grow.

In general, there are two ways to get rid of oxalis in your lawn.

Pull by hand. Oxalis can be removed by hand or dug up using a hoe or spade. To prevent spreading seed throughout your lawn, plants should be removed while they're still young and developing, before the flowers and seed capsules form. The entire root system must be removed or the plant will grow back from any pieces left in the soil.

Use a weed killer. For a few scattered oxalis weeds in the lawn, use a ready-to-use product like Scotts® Spot Weed Control for Lawns. Be sure to select one that is labeled for your lawn's grass type and always follow the label directions.

A large oxalis problem should be treated with a product meant for broadcast application. To kill weeds and feed your lawn at the same time, use a product like Scotts® Turf Builder® Triple Action or Scotts® Turf Builder® Weed & Feed3. If you have a problem with oxalis in a St. Augustine, centipede, or zoysia lawn, try Scotts® Turf Builder® Southern Triple Action or Scotts® Turf Builder® Bonus® S Southern Weed & Feed3 instead.

Prevention & Maintenance

Follow these tips to help keep oxalis from taking over your lawn.

Feed your lawn. Regular feedings (2 to 4 times per year) provide the nutrients your lawn needs to grow thick and strong. A thick lawn will help crowd out weeds like oxalis and prevent weed seeds from germinating.

Mow high. Mowing at the height best for your lawn type allows the grass to grow thick and develop a deep root system. Kentucky bluegrass, perennial ryegrass, fescues, and St. Augustine lawns prefer to be mowed at 3 to 4 inches. Zoysia and centipede lawns do best when mowed at 2 to 3 inches, while bermuda lawns prefer a 1.5 to 2 inch height. Instead of bagging grass clippings, leave them on the lawn to help recycle nutrients back into the soil.

Water deeply. Watering deeply and infrequently helps your lawn outcompete weeds by encouraging deeper root growth and thicker, stronger grass. Watering too little or too frequently encourages shallow root growth, which can lead to a thin lawn and bare spots that weeds will take advantage of. As much as possible, rely on rain (nature's sprinklers) to water your lawn and only use sprinklers when needed to achieve the 1 inch of water per week that most lawns need.