It’s a beautiful spring day, and you’re tempted to walk barefoot across your lawn. It can be a painful experience if you have a nasty cool-season weed called burweed (Soliva sessilis) growing in your turfgrass. When the spring temperatures begin to warm up, this signals the plant to produce seeds. The seeds have sharp spines that will stick to anything they contact, including your bare feet and your pet’s paws. The stickers will also embed into the soles of your shoes, enabling seeds to be spread further around your landscape.
Spraying now to eliminate the mature plants is futile as the hot weather (temperatures above 90° F) will soon kill them. Preventing the seeds from germination is the best means of control. There are several steps to controlling this noxious weed. The first and most important step is to establish a healthy lawn by properly watering, fertilizing, and maintaining your turfgrass. Every fall, apply a pre-emergent herbicide in late September or early October to help prevent the burweed seeds from germinating and water in well. If you have had a heavy infestation of burweed the prior year, you may have to repeat the pre-emergent herbicide application eight weeks later.
The ideal time to use a post-emergent herbicide is in December, January, or February, before the burweed has a chance to flower and produce seed. Be sure to read the label carefully for mixing, application, and temperature requirements.
All lawns have to be at least six months old before applying pre-emergent or post-emergent herbicides. Applying a pre-emergent herbicide in the fall is not an option for a fescue lawn overseeded every fall. The pre-emergent will prevent your fescue seed from germinating.
Your feet and your pets will thank you.
For more information on controlling burweed, see HGIC 2323, Burweed.