One of my goals this season is to improve my knowledge of weeds. I’m good at telling the difference between a wanted plant and a weed – I think this is because I know what a lot of cultivated plants look like. But when it comes to weeds, I know they don’t belong but I can’t always identify what they are. So here’s the first of a number of posts about weeds that I’m seeing in the garden.
The weed that I’m seeing everywhere as I drive around this part of PA is wild garlic (Allium vineale). Wild garlic is most visible in lawns. The grass hasn’t started to grow but in many lawns you can see tufts of grass-like growth that are 6-8 inches taller than the surrounding lawn. They’re especially obvious in lawns planted with zoysia grass. In March these lawns have no green in them at all and are a uniform straw color. If there is wild garlic in a zoysia lawn, the bright green of the garlic sticks out like a sore thumb in the sea of yellow.
This weed has grass-like leaves that have a strong onion/garlic smell when you crush them. You can notice the smell when you mow a lawn with wild garlic in it. The plant produces bulbs like it’s cultivated relative, only much smaller. It grows in the spring and early summer but once the weather warms, the leaves senesce (die) and you can’t tell that the plant is there until next spring. Wild garlic likes rich soil so it’s not surprising that it’s found in lawns. While it can be a problem in agricultural settings – a cow eats from a pasture with wild garlic in it and suddenly the cow’s milk has a garlic smell! – for the home gardener it’s more of a nuisance than anything else.
There is another weed that’s almost identical to wild garlic and that’s wild onion (Allium canadense). It looks like wild garlic, grows like wild garlic and smells like wild garlic. It’s in the same family as wild garlic and is controlled like wild garlic. The one difference is the leaves. If you take a leaf of wild garlic and break it in half, you’ll see that the leaf is hollow and round. Wild onion has leaves that are flat and solid. I’ve done some checking and all of the Alliums that I’ve seen in yards this spring are wild garlic.
There are herbicides that will kill wild garlic if the infestation is heavy. If you only have a few clumps of it in your yard you can ignore it, knowing it’s only a problem in the spring. You can also manually keep the leaves of the wild garlic cut to the height of the lawn – this might not get rid of it but it will weaken the plants over time. If you want to eradicate a few clumps from your yard, here’s a suggestion. Wet a paper towel with Round Up (active ingredient glyphosate – a non-selective herbicide that will kill almost any green plant) and use the towel to wet the leaves of the wild garlic with the herbicide. This will deliver the Round Up to the leaves of the weed without getting it on your lawn. The one thing you want to be sure to do if you try this technique is to wear rubber gloves – getting an herbicide on your skin isn’t a good idea!
So that’s the weed(s) du jour – wild garlic (and wild onion).