Wild garlic (Allium vineale) and wild onion (Allium canadense) are winter perennials. They emerge in late fall from underground bulbs and grow through the winter and spring. In late spring, aerial bulblets are formed and the plants die back in early summer. The underground bulbs can persist in the soil for several years. While both have thin, green, waxy leaves, those of wild garlic are round and hollow, while those of wild onion are flat and solid. Chemical control: Unfortunately, there are no preemergence herbicides that will control wild onion or wild garlic. They must be treated with a postemergence herbicide, and persistence is the key. Plants will need to be sprayed more than once and for more than one season. One characteristic that makes control difficult is that both have a thin, glossy leaf to which herbicides don't readily adhere. Adding a spreader-sticker to the spray solution will help it to adhere evenly. Be aware that some products have a spreader-sticker already added. Unlike most weeds, mowing wild garlic or wild onion immediately before applying an herbicide may improve uptake. After application, do not mow for at least two weeks. Timing of sprays: Treat wild garlic and wild onion in November and again in March. However, be careful not to apply most weed killers onto centipedegrass or St. Augustine grass during their spring green-up period. Inspect the lawn the next fall and spring and treat if necessary. Please refer to the following Clemson Cooperative Extension publication for the recommended herbicides and their application: Wild Garlic & Wild Onion HGIC 2311.