Chisago County Master Gardener
This year’s weeds are producing a bumper crop.
I’m thankful for the weeds that pop out easily when pulled and curse the ones that seem determined to stay put.
Luckily, part of my garden was treated early in the season with Preen, so that part is more manageable. I never got to the rest, and it’s a real mess out there.
One weed that I get every year, but this year is literally out of control, is yellow wood sorrel, Oxalis stricta. This short-lived perennial acts like an annual in Minnesota. Its weak stems, 4 to 18 inches long, branch near the ground. Small, heart-shaped leaves grow in clusters of three, giving a clover-like appearance. Small bright yellow flowers each have five petals; they usually appear in early summer and bloom throughout the season.
Each flower produces a five-sided seed pod which bursts when ripe, spraying seeds. With such an effective seed dispersal mechanism, it’s no wonder that yellow wood sorrel spreads easily. It is common in pastures and waste places as well as lawns and gardens.
In the lawn, wood sorrel grows in bare spots. So a good way to keep it under control is to have a healthy, thick turf.
Pulling is another method. Thankfully, this is one weed that pulls out very easily.
If you choose to spot- spray, use a product that targets weeds like wood sorrel. Do not use Roundup, because that will kill the grass. Some pre-emergent herbicides, like the ones used for crabgrass control, can help. These are applied in mid-spring, but again, make sure the label mentions yellow wood sorrel.
In the flower or vegetable garden, mulch the beds with two to three inches of organic matter to prevent yellow wood sorrel from making itself at home.
Most yellow wood sorrel is under 6 inches tall, but I’ve had plenty stay hidden and grow a foot high by the time I found them. Believe me, you can pull this weed all day long and think you’ve got it all, but there’s always more lurking.
On a positive note, all parts of yellow wood sorrel are edible, with a bright, tangy flavor. The leaves and blossoms can be added to salads as a decorative touch, and a lemony drink can be made from the foliage.