What is Wild Onion and How Do I Control It?

Not only is wild onion extremely invasive, but it’s perennial, which means it will return year after year until you take action to get rid of it once and for all.

While you may welcome garden-grown onions to your kitchen, that doesn't mean you want their wild cousins hanging out on your lawn. Not only is wild onion extremely invasive, but it's perennial, which means it will return year after year until you take action to get rid of it once and for all. Unfortunately, mowing it down won't stop this tenacious weed from sprouting right back up again. But you can fight back in other ways – and win.

Identifying Wild Onion

Though similar in appearance to wild garlic, wild onion has flat, solid leaves, while the leaves of wild garlic are round and hollow. Wild onion also produces bulbs and is cousin to the culinary onions grown in the garden. If the clusters of thin leaves that grow to about a foot tall aren't enough to help you ID this interloper, the strong onion smell that wafts up when the plant is cut or mowed is a dead giveaway. Wild onion will begin to appear in your lawn in the fall as the temperatures start to cool, then eventually go dormant early the following summer when it starts to get hot. It grows in patches and thrives in both shade and full sun.

3 Steps to Control Wild Onions

Don't Pull Wild Onions by Hand
Wild onion leaves are brittle, which makes it difficult to pull the plant cleanly from the soil. Even if you do manage to pull up the main plant, chances are there will be small bulbs left behind in the soil that will be more than happy to grow and continue to plague you.
Maintain a Thick Lawn
Like other weeds, wild onion will have a hard time making inroads if your lawn is thick and lush. While thin and sparse grass acts like a neon "Vacancy" sign for weeds, a well-maintained lawn doesn't leave any room for weeds to take up residence. To combat a thin lawn, you may need to overseed it to start it on the road to thickness, then keep it thick with regular feedings (4 times per year) of lawn food.
Use Roundup® For Lawns
To beat wild onion where it grows, use Roundup® For Lawns in the early fall when it first becomes noticeable. Know, too, that you may have to do a second application in the spring. For small patches of wild onion, a ready-to-use version of the product is best, but for a wide-spread wild onion problem, opt instead for a ready-to-spray or concentrate version.