How to Get Rid of Onion Grass in a Lawn

Onion grass, the common name for Nothoscordum gracile, can overrun a lawn or garden and kill vibrant grass and other plants. While there is no miracle solution, digging up existing onion grass by its roots should help you get rid of large problematic areas. After removing the grass by its roots, be vigilant in looking for the first signs of new growth. This will enable you to eradicate the problem before it gets severe again.

Things You'll Need

• Thin sticks or wooden dowels
• A spade or small pointed shovel
• White vinegar
• Large plastic spray bottle
• Weed killer
• Lawn mower

Instructions

1. Mark any areas of onion grass growth in your yard by placing a thin stick or dowel next to problem areas. No matter how small any area may be today, by next week it can develop into a full-blown weed problem. Do not neglect even the smallest patch.

2. Start digging in one area and finish each area before moving to the neighboring area. Remove the dowel or stick as you finish the area. Dig out the offending weeds with the spade. Be sure to dig beyond the root you see. The weed can have left behind "bulbils" (small offshoot bulbs) that will allow the onion grass to reappear.

3. Pour vinegar into the spray bottle. Squirt the vinegar into the soil making sure that you have soaked every area that might have been touched by the onion grass. Allow this to set for a few hours during a sunny day. Refill the holes with the soil you removed. This may do some light temporary damage to the grass around it, but with the onion grass gone, the lawn will grow back greener and healthier than ever.

4. Mow the lawn on a regular basis. Look for new growth while mowing. As soon as you see any new growth, use a spade and dig it out. Apply some vinegar. If this method does not work, and the weeds come back in a great quantity, buy a commercial weed killer containing glyphosate.

5. Follow the directions for application on the glyphosate container. You will likely have to make repeated applications. Glyphosate is a systemic herbicide, and will kill other plants it contacts, so it might kill your grass, too. In the end, the best solution might be simply to dig up the infested parts of the lawn including at least 4 inches of the soil, dispose of it responsibly, and replace your soil and grass.

References

• Our Brisband: Onion Grass/Onion Weed
• Garden Guides: How to Get Rid of Onion Grass in a Lawn