Type of Weed: Broadleaf
Oxalis is a broadleaf perennial weed that is often mistaken for clover. This weed prefers full sun and moist, fertile soil, while also being able to tolerate a range of conditions once established.
Oxalis typically grows in the warmer months of May to September, but for warmer states, it can grow year-round.
The two common oxalis weeds in the Dallas Forth Worth area are yellow oxalis and creeping oxalis. With leaves and flowers similar in appearance, their root system is key to distinguishing the two.
Yellow oxalis spreads underground by their rhizomes while creeping oxalis spreads above ground by their stolons.
How to Identify
It produces a five petaled yellow flower that forms singly or in clusters of five on a long stalk. These flowers can bloom in spring, summer, and fall. Yellow oxalis’ seeds are tiny and formed in pods resembling small okra. These seeds can be ejected several feet from the main weed.
Creeping oxalis looks almost identical to yellow oxalis. The key differences are that it grows prostrate, creeping along the surface, and its leaves, stems, and seed pods are green to reddish purple in color, while also producing single yellow flowers or in clusters.
For young or small infestations of oxalis weeds, you can pull them up by hand or dig them up, ensuring you get all of the root system so it does not have a chance to grow back from remnants of roots in the soil.
This is most effective before the weed has flowered, which will prevent the seeds from ejecting distances all around. After mechanical control in a flower bed or natural area, cover with a dense layer of mulch, this will block out light and make it more difficult for oxalis to re-grow.
For bigger infestation, the use of a selective broadleaf herbicide during the growing season will be most effective if applied before the weed has flowered.
To further prevent oxalis from infiltrating your lawn or natural areas, apply a selective pre-emergent herbicide in late fall and early spring, to prevent the seeds from germinating.
Combining this with an application of selective post-emergent herbicide during the growing season will be the most effective way to combat oxalis.