How to Get Rid of Onion Grass

Wild onion (Allium canadense) is an unsightly, perennial weed that invades grassy areas, such as your lawn. It belongs to the lily family and is poisonous if ingested. For this reason, when you identify wild onions growing in your lawn, take measures to kill the weed. If you leave the bulbs in your lawn, the bulbs split, producing more wild onions.


How to Identify Wild Onions

The first step in getting rid of wild onions is to identify them. Many people mistake the Star of Bethlehem for wild onion because they look very similar. Look for the following characteristics, if you think you see wild onions growing in your lawn:

  • Flat, solid leaves
  • Leaves attached to the bottom of the stem
  • Stems growing from a basal bulb
  • Stems have an onion smell
  • Clusters of bulbs underground

Organic Methods for Getting Rid of Onion Grass

Wild onions are hard to control and bulbs can remain dormant for years before they sprout, which makes control even harder. Following a few methods for controlling wild onion growth can help keep them from invading your lawn. When you mow your lawn, make sure you don’t cut it too short because the onion bulb prefers short, unfertilized lawns.

Ornamental and Vegetable Gardens

If you notice onion grass in your ornamental beds, such as rock gardens or flowerbeds, you can dig up the bulb clusters, pulling them out by the stems. Moisten the soil before you do this because the soil will be softer. This allows for the removal of all the small, white bulb clusters. You can use this same method if you find this weed in your vegetable garden. Covering your gardens with plastic during the off-season can prevent the emergence of stems in the spring.


It’s harder to control onion grass in your lawn. If you keep your turf healthy and dense, it can prevent the onion grass from establishing itself in your grass. When you do see it in your lawn, use a weeding tool to loosen the bulbs from the soil. This can be difficult, if you don’t want to damage your existing lawn. This method works the best when you catch the weeds while they’re still young.

If you find that it’s too difficult to pull out the wild onions, regular mowing can keep them in check. Although, it won’t kill the onion grass, it will weaken the plants and stop them from spreading.

Organic Herbicides

Using organic herbicides is another option, but you must be persistent in applying several applications before you kill the onion grass. One application won’t do it. Before applying, injure the leaves, so the herbicide can enter the plant. You can grind your foot on the leaves to open up spots for the herbicide. The problem with using commercial herbicides is that they might damage your lawn, if any residue falls on the grass. Always check the label to make sure it’s a safe, organic herbicide.