Many species of oxalis are lovely additions to the garden and landscaping. If your garden is graced with oxalis stricta (yellow wood sorrel), however, enjoyment can turn into frustration. The oxalis stricta plant is an invasive, stubborn weed that can choke out wanted plants, survive all but the strongest attacks and thrive for decades. Here's what you need to know about eliminating oxalis from your garden.
Use an ammonium thiosulfate treatment to kill oxalis on the surface. Protect surrounding plants with plastic or paper, and spray only the oxalis plant, leaves and stem. This and other weed killers, such as Roundup, are temporary solutions at best, and must be repeated regularly as new oxalis plants sprout.
Suffocate oxalis plants by covering the area with black plastic or newspaper, then topping with mulch. This method can take from several months to several years to completely eliminate the oxalis plant, so patience is a necessity.
Locate the base of the oxalis plant, a small bulblet, and dig up the entire unit, including the shoots, stems and leaves. Any remaining bits of the oxalis have the potential to sprout new plants, so thorough eradication may be impossible.
Weed oxalis plants out of beds regularly. This will not kill off the oxalis entirely, but will prevent it from overtaking your wanted plants. If the oxalis invades potted cacti and other succulents, use a long pair of tweezers to remove the plant from between the sharp needles.