How to Get Rid of Onion Weed

Onion weed (Allium Triquetrum) has a sweet, dainty snowbell flower. Yet, this seemingly pretty plant is in reality a stinky visitor to the garden. When it is crushed, or even just growing in large numbers, It can cause an unpleasant odor.


  1. Image titled Get Rid of Onion Weed Step 1
    Understand the basics of this weed. It is highly invasive and multiplies through the division of bulbs and also by seed. This makes it a rapid grower and difficult to shift once it has taken hold.
  2. Image titled Get Rid of Onion Weed Step 2
    Mow the weed out. Be relentless and continue to mow over the weed. Eventually this exhausts the bulbs and they die off. You have to be consistent, regular and determined with the mowing, however.
  3. Image titled Get Rid of Onion Weed Step 3
    Dig the weed out. Often onion weed perches where no lawnmower will ever manage to go. This requires the determined gardener to wield the shovel and go and dig the weeds out. This is no mean feat and should be done by the fit only. Get a helper if that isn't you. Unfortunately, digging can often disturb the bulbs and lose some of them back to the soil in the process, to regrow next season. Don't lose heart; keep at it.
  4. Image titled Get Rid of Onion Weed Step 4
    Cut them down. If you can't mow them, and digging is just too tiring for you, try cutting them. Use long shears and continue to lop them off, time and time again. As with the lawnmowing, eventually this will exhaust the bulbs and they'll give up.
  5. Image titled Get Rid of Onion Weed Step 5
    Spot spray or wipe. Ask your local garden centre for a suitable spray or wipe-on weed killer and use strictly in accordance with the instructions. A lot of gardeners do not like resorting to spraying or using chemical solutions, and with good reason. If you do resort to this solution, ask for a spray or wipe-on weed killer that does not impact human health, can be spot sprayed directly on the weed rather than around on other plants (wipe-on's already do this by definition) and is short-lived so that its effects are very controlled. Always spray on a clear, non-windy and dry day.


  • The bulbs and leaves are edible. Pickle the bulbs for a version of baby pickled onions.[1]
  • Sprays suggested for onion weed include Roundup™ (glyphosate) or Amitrole™. Amitrole is a rub-on version that enters via the leaves into the bulbs and transfers between bulbs.[2] It has also been suggested that glyphosate is more effective when rubbed on rather than sprayed.[3]


  • Never let it to get to the point of going to seed! That spreads it more than anything.
  • Always wear garden gloves if you use a wipe-on weed killer product.

Things You'll Need

  • Shovel/spade/trowel
  • Garden shears
  • Spray (optional) or wipe-on weed killer

Sources and Citations

  1. Grown-Ups, 50+ Community, Onion Weed
  2. Grown-Ups, 50+ Community, Onion Weed
  3. See Gardening Australia, Onion Weed Issue.

Article Info

Categories: Garden Pests and Weeds