Christo Sullivan, Doug Martin, Jordan Billingsley
About – Yellow Woodsorrel (Oxalis stricta) is a medium-sized edible plant that thrives in lawns and woodlands across the United States and Canada. It can also be found in Europe, Africa, Asia, Japan and New Zealand. The flowers can be used to make yellow, orange, red and brown dyes. Another common name is “Oxalis”, which means “sour” due to its oxalic acid content. Oxalic acid can be toxic when consumed in large quantities because it inhibits the absorption of calcium. Yellow Woodsorrel is a cool season perennial in the Woodsorrel family (Oxalidacea), but may act as a summer annual in certain environments. It reproduces by seed and occasionally stems.
Identification – Yellow woodsorrel introduces itself from a taproot and forms small, erect, bushy plants up to 20 inches tall. The stems are slender, gray-green, pubescent, slightly ascending, and branched at the base. They will occasionally root at the nodes. The leaves of yellow woodsorrel are alternate with three heart-shaped leaflets. They are pale green, up to 4/5 inch across with long petioles. The flowers are yellow with five petals and are up to ½ inch across. It is often mat forming and more common in cools-season turf species, such as tall fescue. It can be very common in greenhouses and container nurseries because its seedpods can distribute seeds up to several feet.
Cultural– Hand-weeding is effective before seeds are formed. As always, the best weed control is a dense turf sward. Proper mowing, fertilizing and irrigation ensure vigorously growing turf.
Many pre and post-emergent herbicides are effective.
Pre-emergent herbicides include:
Post-emergent herbicides include:
And many 3-way mixtures sold at in lawn and garden sections (often labelled as Trimec Southern or for Broadleaf weed control).