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“Do you have something that can remove onion weed?” was a frequent question we were asked at the Sydney Home Show this Spring.  We’ve done some research on the experts to get you than answer on removing this unwanted guest from your garden.

1. What is Onion Weed?

Onion weed is a perennial thug that produces thin spiky waxy leaves to which pesticides cannot attach to.  It is also known as wild garlic or wild onion and grows from bulbs which in the summer produces a flower spike and seeds which are carried by the wind.  It can spread at a rate of knots making it difficult to control.

Onion weed is classed as a noxious weed for most of NSW and WA, and for all of TAS, SA and VIC.  It can quickly take over your garden, impacting your plants and eliminate all your hard work in the garden.  

2. Impact of Onion Weed on Your Garden

Despite being pretty to look at and like something you’d add into your salad, onion weed likes to take up a lot of space, nutrients, sunlight and water in your garden.  Your other plants won’t get a look in as the onion weed reaps the benefits of all your work.  Your plants development and health will start to suffer.

Now, onion weed also likes to give, especially when it comes pests and illnesses that can spread quickly to your other plants.  These are two very good reasons as to why you need onion weed out of your garden

3. Why is Onion Weed so difficult to control?

This is a tough one to control due to:

  1. The weed grows from bulbs making it difficult to dig out completely and prone to leaving small pieces of the bulb behind.  Then you’re back to square one
  2. The onion weed also produces smaller bulblets that quickly grow into new plants.
  3. Finally, the leaves on onion weed have a waxy coating that make it near to impossible for herbicides to kill the plant.

4. What is the cycle of onion weed?

Winter: germination

Spring: growth and spread

Summer: dormant

Autumn: growth and spread

5. How can I kill onion weed naturally?

You’re probably thinking onion weed is indestructible and your garden is doomed.  Fear not!  There are ways to remove this pest from your garden without harsh chemicals.

Digging

Digging with a spade or hoe is the best option to keep on top of the weed.  It’s hard yakka and you have to make sure you dig deep to remove the entire bulb and and bulblets.  

Onion weed is pretty hard to dispose of – avoid putting them into your compost or the green waste straight away.  Put them in a plastic bag or sealed container to prevent them growing.

Smothering

Use thick newspaper, cardboard or mulch to smother the onion weed.  This will deprive the plant of any sunlight and after a few weeks, the plant will die.

Vinegar

Who knew vinegar could be a good weed killer?  Vinegar is a natural herbicide and is tough enough to handle onion weed.  Simply mix equal parts vinegar and water in a spray bottle and spray all over the plant, including the bulb and leaves.

6. What is the best way to dispose of onion weed?

Onion weed is an unbelievably resilient plant to say the least!  The actual bulb and seeds will still be growing strong even when they are extracted from the plant.  The best way to dispose of the onion weed and prevent any further infestation is to put all of it into a bag to dry out in the sun.  Then, discard this bag into the general garbage bins – do not add to your compost or green recycling bin as the onion weed will continue to spread if you use the compost again.

Finally, give your garden tools you have used to remove the weed a really good clean.  This will prevent reintroducing and residual seeds back into your garden.  I told you this is a resilient plant!

7. How can I restore my garden or lawn after I have removed the onion weed?

Getting your garden back on track after an onion weed infestation takes some TLC.  For your lawn, fill in any holes with some healthy top soil.  Apply a good dose of lawn fertiliser to help restore nutrients and encourage growth.

For garden beds, add some compost to restore the nutrients in the plants and plant fast-growing plants to prevent any leftover onion weed starts taking up all the room.  Apply a good layer of mulch over any bare soil to block sunlight and restrict growth.

8. How can I prevent onion weed from growing?

Follow our handy tips and this will you keep on top of this annoying, unwanted visitor in the garden:

  • Mulch to block sunlight and growth
  • Regularly weed your garden, especially the onion weed to prevent them from spreading
  • Always clean any garden tools that you have used to remove the onion weed before using them elsewhere in the garden
  • Check any new plants and bulbs for onion weed before you plant them

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