Yellow Wood Sorrel: Identification, Removal, and Prevention
Identification
Yellow wood sorrel (Oxalis stricta) is a common weed that resembles clover. Its leaves are heart-shaped and radiate from a central point like fingers from a palm. The stems, branches, and leaf stalks have fine hairs.
Wood sorrel has a bright green color and produces small, yellow, five-petaled flowers from mid-spring to fall. The flowers are about 1/2 inch in diameter. The plant typically grows up to 20 inches tall and forms thick clumps.
Invasiveness and Spread
Yellow wood sorrel is considered an invasive plant in some areas, such as Kentucky. It spreads rapidly through horizontal stems (runners) and seeds that take root where they touch the soil.
The seed pods can hold up to 5,000 seeds, giving the plant ample opportunities to overtake gardens and other areas. Additionally, the seeds can be dispersed by wind, animals, and clothing, facilitating its spread.
Removal
Yellow wood sorrel can be removed by hand or using chemical methods.
Hand Removal
To remove the plant manually, dig it out or pull it up by the roots, ensuring to remove as much of the root system as possible. The roots are extensive and can resprout if left behind.
Chemical Removal
Glyphosate (Roundup) is an effective chemical solution for killing yellow wood sorrel, including its roots. It is a broad-spectrum herbicide, so care should be taken to avoid harming other plants.
For lawns, post-emergent herbicides containing triclopyr (cool-season turfgrass) or fluroxypyr (warm-season turfgrass) can be used to target wood sorrel without affecting the grass.
Prevention
Preventing yellow wood sorrel from establishing in the first place is crucial. Some effective methods include:
- Maintaining a Healthy Lawn: A thick, healthy lawn can outcompete wood sorrel for resources. Seed or sod any bare spots to prevent the weed from taking hold.
- Mulching Garden Beds: Mulch helps suppress weed growth by blocking sunlight. Use a two- to three-inch layer of organic mulch to prevent wood sorrel from germinating.
- Diligent Inspection: Regularly inspect your lawn and garden beds for signs of wood sorrel. Remove any plants as soon as they appear to prevent seed production.
- Herbicide Application: Post-emergent herbicides can be used to control existing wood sorrel and prevent its spread. Apply them in the late spring when the weeds are actively growing and before they produce seeds.
Distinguishing Yellow Wood Sorrel from Clover
Yellow wood sorrel is often confused with red or white clover, but there are key differences:
- Leaf Shape: Wood sorrel has heart-shaped leaves, while clover leaves are oval-shaped.
- Flower Color: Wood sorrel has bright yellow flowers, while white clover has white flowers and red clover has pink flowers.
Additional Information
- Edible Uses: All parts of yellow wood sorrel are edible and have a tangy flavor. It can be added to salads or used to make teas or other beverages.
- Toxicity: Yellow wood sorrel contains oxalic acid, which can be toxic to cats, dogs, and livestock in large amounts.
- Misidentification: Wood sorrel is sometimes mislabeled and sold as shamrock during St. Patrick’s Day season.
