Sometimes mistaken for clover, oxalis is an invasive perennial weed that is difficult to eradicate. This flowering plant may be pretty enough to perk up your landscaping, but once it’s in your yard it spreads rapidly, taking over gardens, lawns, and even potted plants. Oxalis flourishes in many areas across North America and although it’s very tolerant of shade, it also grows well in full sun with adequate moisture. Edible in small amounts, some species are known as sourgrass because of their acidic content and sour, citrusy flavor.

Identifying Oxalis

There are somewhere between 800 and 900 species of oxalis, but the wood sorrels (Oxalis corniculata) are the the largest and most well known. Other common names for this wild weed are creeping woodsorrel, yellow woodsorrel, yellow oxalis, and false shamrock due to its three heart-shaped leaves. Although yellow is the most familiar, some species have purple, white, or pink flowers.

Oxalis Signs and Symptoms

Oxalis blooms from mid-spring well into fall. Its petite five-petal flowers and leaves range in color from pale green to purplish green. The low-growing plants have a fibrous root system that’s difficult to dig out in entirety. Although its stems root where they touch the ground, this aggressive plant spreads mostly by seeds that are discharged from pods. Each plant generates up to 5,000 seeds that are then ejected from the ripe pods up to a distance of 10 feet. The leaves of the wood sorrel fold up at night, or when under stress, and reopen in the morning.

Oxalis Management and Prevention

Oxalis quickly takes over lawns that are sparse, poorly maintained, or damaged from insects or disease. So, the first step in preventing a weed invasion is to keep your yard well-maintained.

  • Regularly feed or fertilize your lawn to keep it at its healthiest.
  • Mow your lawn at the proper height. This encourages a well-developed root system and thick, lush turf that won’t let weeds take over.
  • Don’t overwater – frequent light watering encourages the weed’s growth. Rely on the rain or use only one inch of water with a hose or sprinkler.
  • Use mulch in gardens, borders, and plant beds to control weed growth.

If you find this weed in its early stages, you may be able to pull it out by hand. This is very tricky, though, because the root systems are very intricate and often part of it gets left behind. Another reason this method is not always successful is that the weed must be pulled before it flowers and sets seed. If it has developed seed pods, be sure to remove them carefully so they don’t burst and disperse the seeds. Carefully dispose of the pods in a sealed garbage bag.

When dealing with an invasion of oxalis, you may need to use a chemical weed killer. Finding the right one is a challenge since some species are resistant to certain chemicals. Try a broadleaf weed herbicide such as glyphosate. Or for an organic option, use a chelated iron product. Oxalis can not tolerate an overload of iron.

If you want to learn more about identifying and controlling oxalis or other weeds, contact Free Spray Lawn Care at [phone].