Lawn-weed question - Ask Extension
Every summer (for years) I get a weed infestation that develops in a small area of my back lawn beginning in June and continuing through July and Augu...
Knowledgebase
Lawn-weed question #940542
Asked July 26, 2026, 11:00 AM EDT
Every summer (for years) I get a weed infestation that develops in a small area of my back lawn beginning in June and continuing through July and August. I've tried to eliminate these plants using Ortho spray and other weedkillers without success. Nothing seems to work; these weeds always return and appear to be unstoppable...
Pictures are attached. What is this stuff and what can I do to get rid of it?
Thank you for your help.
Wayne County Michigan
Expert Response
Hello
These appear to be Hibiscus syriacus seedlings, also known as rose-of-Sharon or Althea. They will die as you consistently mow them down when cutting the lawn.
To prevent new seedlings, dead head any rose-of-Sharon shrubs before they set seeds. Clip off the seed capsules while still green and discard.
Putting down a pre-emergent herbicide such as one containing trifluran or a crabgrass pre-emergent before they sprout, such as late in May, can help prevent many of them from developing, too.
Here is more on the shrub, so you can identify where it is in your landscape.
https://plants.ces.ncsu.edu/plants/hibiscus-syriacus/
https://ag.missouristate.edu/PBTrewatha/althea.htm
These appear to be Hibiscus syriacus seedlings, also known as rose-of-Sharon or Althea. They will die as you consistently mow them down when cutting the lawn.
To prevent new seedlings, dead head any rose-of-Sharon shrubs before they set seeds. Clip off the seed capsules while still green and discard.
Putting down a pre-emergent herbicide such as one containing trifluran or a crabgrass pre-emergent before they sprout, such as late in May, can help prevent many of them from developing, too.
Here is more on the shrub, so you can identify where it is in your landscape.
https://plants.ces.ncsu.edu/plants/hibiscus-syriacus/
https://ag.missouristate.edu/PBTrewatha/althea.htm
Hi Laura:
Thank you for your quick response. Yes indeed, we have a rose of Sharon “tree” directly above these seedlings, clearly the source!
You have been very helpful. Thank you.
Sincerely, Greg
On Jul 26, 2026, at 11:27 AM, Ask Extension wrote:
You are welcome. I have the same situation beneath my rose of Sharon too. Instead of just deadheading, I actually wait till most blooms are done and then reduce the shrub by about 1/3 in height, which removes most of the seedheads. Might be easier than just trying to trim seedheads off and keeps the shrub a managable size
Laura
Laura
