Wild onion in dormant zoysia grass
Dormant zoysiagrass lawn with wild onion, a perennial broadleaf weed that sprouts as winter fades and spring approaches.
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One cold-season weed that pops up in a lot of lawns is a plant that looks like a smaller version of the onions and garlic we grow in vegetable gardens. That similarity is more than coincidence. The spiky-leafed little weed clumps really are onion-family relatives known as “wild onions” and “wild garlic.” Both can be identified by their oniony scent. The main difference is that wild garlic has round, hollow leaves while wild onion’s leaves are flat and solid.

Once seeded into a lawn, wild onions and wild garlic send up their slender green shoots in late fall through winter. If not mowed, the plants produce small bulblets at their tips in spring. These bulblets carry seeds that create new plants the following year. Plants then go dormant and die back as the weather warms in later spring. However, the underground bulbs don’t die but start a new growth cycle when cool weather returns, producing additional underground bulblets from the “mother” bulb in the process.

Dealing with wild onions and wild garlic

Smaller outbreaks of wild onions and wild garlic can be stopped by digging them out. You’ll need a long, sharp weeding tool (even a screwdriver will do) to help lift out the entire bulb cluster. This is most effective when the soil is damp and loose. If you just rip off the leafy tops or hand-pull the clumps, you’ll leave behind bulbs or separated bulblets that will re-emerge. Mowing regularly slows the plants’ spread by short-circuiting their ability to produce those seed-containing tip bulblets.

If you have too many wild onions or garlic in your lawn to dig, a granular herbicide will do the job for you. GreenView Fairway Formula Spring Fertilizer Weed and Feed with Crabgrass Control is a single application product that combines three spring lawn treatments that stop crabgrass all season, feed your lawn, and kill unwanted weeds such as dandelions, plantain, clover, wild onions, and wild garlic.

Once weeds have been addressed, the best long term solution is to thicken the lawn by overseeding with additional grass seed. Thick lawns make it hard for any other plant to elbow its way in. In most regions of the U.S., early spring and early fall are the two best times of year to overseed thin lawns.

Areas where you’ve dug out weeds can be seeded immediately. Scratch the soil surface to aid germination, and keep the newly seeded patches consistently damp until the grass blades are up. In areas where you’ve used herbicides, read the product labels for instructions on how long to wait between application and seeding.