On the top of my list of lawn related annoyances is stepping into a patch of burweed, Soliva sessilis, which is in the sunflower family and is also known as spurweed. The leaves are opposite along the stem and sometimes resemble parsley. The main ways in which burweed can irk the casual gardener are sticking to socks, sneaking in with the dog, or littering flower beds with its nuisance. It can also hide in the house and reappear when shoes are removed. This causes pain in both the foot and the ear.
Lawn burweed has been an especially noticeable problem in lawns. Over the years, extension offices throughout Northwest Florida have been fielding many questions and finding solutions to lawn burweed infestations!
Maintaining a healthy vigorous lawn will prevent weeds from taking over. If your lawn is reasonably healthy and only a few instances of this weed exist, try to mechanically remove them and encourage the lawn to outgrow them.
If an infestation of burweed occurred last year on a specific patch of turf, take note. The best time to apply pre-emergent herbicides to control burweed is in October, when nighttime temperatures drop to between 55-60 degrees F for a few consecutive nights. A widely used pre-emergence product for burweed control is isoxaben, which is sold under the brand name of Gallery as well as others. It prevents the weed from emerging from the ground when it germinates and can be used on St. Augustine, centipede, bahia and zoysia lawns, as well as in ornamental shrub beds. In northwest Florida, this herbicide needs to be applied in October for best results. A second application later in the season might be warranted. For more information about control, please consult this excellent article on lawn burweed management.
Now is the time to control burweed before it gets started. As temperatures cool burweed seed will germinate, as it is a winter annual. In cases where it is already coming up, control with post-emergent herbicide may be warranted.
The active ingredients mentioned above are present in a variety of ‘trade name’ products* available from your local garden center, farm supply or co-op. Be sure to read label instructions carefully and contact your local extension office for any assistance. I hope all the northwest Florida lawn managers prevent burweed this fall so that lawns will be burweed free next spring.