I detest onion weed, but every winter when I venture out into the cold there are signs it’s not giving up on me. Long leaf blades are emerging in the lawn, poking their way out of brickwork or taking advantage of bare spots in garden beds. I may fleetingly think optimistically that they’re early signs of daffodils that promise to brighten up my spring, but that’s delusional. It’s the dreaded onion weed. I’m meticulous about keeping weeds out of my garden, so it’s this persistent little blighter that drags me away from the heater, ruining my cosy indoor winter days to ensure it doesn’t ruin my summer in the garden.

Understandably, onion weed is a noxious weed in most of NSW and WA and all of Victoria, South Australia and Tasmania. It’s a perennial so it comes back year after year if not destroyed. Flowers form in late spring, early summer, then the seeds are scattered by the breeze into other parts of your garden or from your neighbours’ areas.

But the weed is also spread when the soil is disturbed in garden beds where it has also settled. Digging in the soil when putting in plants or aerating it can break up the parent bulb into tiny bulbettes or bulbils, from which new plants grow. This is what makes it so insidious.

1. Hit it with chemicals

The quickest and most effective way to get rid of onion weed from your lawns and garden beds is to coat the leaves with a glyphosate-based weed killer.

But it’s also the most damaging to your garden unless you apply it – very carefully – with a wand or brush. This targets the actual weed, rather than your otherwise healthy surrounding lawn or the beautiful plants in your garden beds. Use it If onion weed is growing through cracks in your paving or brick walls and there are no other plants nearby.

Or you can employ the ‘gloves of death’ approach used by a keen gardening friend. She pulls on impervious, plastic gloves, dips her thumb and index finger into a glyphosate solution then wipes both sides of the leaves with the solution.

WARNING Always wear gloves, long-sleeved tops and pants and protective eyewear when using glyphosate as any splashes on your skin or in your eyes will cause irritation.

2. Smother it

Covering the area where onion weed is rife works if you don’t mind sacrificing the surrounding plant life, including your lawn.

Pop into your local bottle store and pick up a pile of empty wine cartons, flatten them and spread on the weeds. This stops the photosynthesis process that sends energy back to the roots. But it does take several months as the bulbs also store energy and the weed won’t die until this energy is exhausted. As the cardboard breaks down, it contributes to the soil’s ecosystem.

Don’t use plastic – this is called solarisation and, while it also stops photosynthesis, the heat generated during this process also kills soil micro-organisms, both bad and good. The soil will recover, but it takes some time.

3. Mow it down

Regular mowing removes onion weed leaves from your lawns, draining the bulbs of their energy as they push new foliage up that get chopped back again on the next mow. But the leaves start to emerge in winter as your lawn is in dormancy. This is an option if you don’t mind the extra effort of winter mowing.

Lawn mower cutting green grass in backyard, mowing lawn

4. Hand weeding

This is the most environmentally friendly way of getting rid of onion weed, but it takes a long time to get on top of the problem. This involves being in your garden every weekend – including winter – and pulling up the leaves as they emerge (sometimes if they’re young and near the surface, you’ll get the bulb at the same time). As with mowing, the bulbs will use their energy to produce new foliage, which next weekend you remove. And on it goes, until eventually the bulbs run out of energy, they don’t have enough left to produce flowers and seeds, and the weed dies. Yay!!

5. Weed mats

Weed mats block the sunlight that weeds need to grow but also let in moisture so the roots of your ornamental plants can thrive. While they’re effective against many weeds, eventually onion weed leaf blades, fuelled by those energy-filled bulbs, will sneak through, so it’s not a viable option in your battle against this villain of the garden.

Weed barrier mats protect the plants you want to keep and are effective against most weeds. Onion weed, however will eventually come through. ( Credit: Adobe Stock )

6. Digging them out

Digging up your garden beds and hand picking out the bulbs is a laborious and painstaking option. While you may retrieve bulbs, in the process some of the bulbils can break away and, because they’re so tiny, you may not notice them. The bulbils will eventually form new roots, produce shoots and the problem returns. Any bulbs you retrieve should be wrapped in plastic and tossed in your rubbish bin, not your compost.

The post 4 effective ways to get rid of onion weed I swear by as a horticulturist appeared first on Better Homes & Gardens Australia.