Wedelia (Wedelia trilobata) is a low-growing perennial with delicate yellow blooms that is often used as a groundcover in hot and dry locations throughout U.S. Department of Agriculture plant hardiness zone 8 through 11. However, its thick, dense-forming growth and fast spreading habit give it an aggressive and invasive nature that can become a problem in your garden. You can kill wedelia with manual or chemical control options, but it may take several treatments before this annoying weed is completely eradicated.
Wear thick work gloves. Grasp the stem of the wedelia plant close to soil level. Pull the plant out of the ground, trying to remove the whole root system. This will help reduce the chance of regrowth.
Place the removed plants into a garbage bag to reduce the chance of the weed spreading.
Monitor the location for regrowth; immediately hand pull seedlings as they emerge from the ground.
Protect desirable plants nearby by covering them with a plastic tarp. Nonselective herbicide will kill any plant it encounters, including vegetation you want in the garden.
Wear protective eyewear and rubber gloves. Herbicides contain toxins that can cause irritation. Wearing protective clothing will help prevent skin and eye irritation.
Mix 2 2/3 ounces of glyphosate-containing herbicide with 1 gallon of water to create a 2 percent solution. This will treat small patches of wedelia plants. For larger, denser patches, mix 6 1/2 ounces of the herbicide with 1 gallon of water for a 5 percent solution.
Apply the diluted herbicides to the wedelia, completely covering the foliage with the chemical. Avoid applying too much to the point of runoff. Monitor the area for signs of regrowth; repeat the chemical treatment as needed.