Knowledgebase
How to get rid of stonecrop sedum in lawn #655648
Asked June 24, 2020, 5:55 PM EDT
Antrim County Michigan
Expert Response
I think this is a related plant called mossy stonecrop (Sedum acre), which is much more common in Michigan. Mossy stonecrop is a perennial weed that was originally introduced as an ornamental, but has escaped cultivation in some areas. It reproduces by seeds, stolons (stems that grow along the ground), and stem fragments.
Control will be the same ultimately regardless of which stonecrop it is. For small patches it can be removed
manually by digging the plants out and disposing of all material (above and
below-ground). For larger infestations, you may want to
explore herbicide options. Standard turfgrass herbicides that target emerged
broadleaf weeds (e.g. dicamba, 2,4-D, triclopyr, etc.) may have some effect,
but may only suppress mossy stonecrop and not achieve complete
control. Another option is to apply glyphosate (e.g. Roundup Weed and Grass
Killer, though there are many others).
When using products containing glyphosate there
are a few important points to consider. First, as with any pesticide, remember
to read and follow all labeled instructions. Second, glyphosate
is a broad-spectrum herbicide, meaning it
will injure or kill other plants contacted during application, so care is
needed to avoid green plant material, exposed roots, and injured bark of
desired plants. You will likely kill some of the lawn in this
case (near the treated area). Third,
glyphosate is relatively safe in the environment when used as labeled. It
adsorbs strongly to soil in most cases (i.e. clay and organic matter), allowing
even sensitive crops to be planted shortly after application; meaning no carry
over issues are expected. Fourth, glyphosate alone can take up to 14 days to
show full activity under ideal growing conditions. Retreatment of the area may
be needed depending on the degree of infestation. Glyphosate is most effective
for perennial control in the fall but can be applied anytime the plants are
actively growing (temperatures consistently above 50F). Finally, be sure that
the product you choose has only the active ingredient glyphosate or glyphosate
+ pelargonic acid. Products with additional active ingredients may have other
unwanted effects and may delay the planting of other plants in the coming
season(s).
You'll want to replant grass once you are sure the mossy stonecrop is controlled. Once
you replant the grass, keep an eye out for any individual plants that may come
up from seed in the following seasons as there is likely a "seed
bank" present that may come up if the opportunity arises.
Once you are rid of the weed there are some
steps you can take to help give your grass a competitive edge. Consider
fertilizing particularly in the late summer, around Labor day, mow at a height
of 3" or greater, and water when the weather turns dry in the heat of
summer. You can read more information about summer lawn care in the free MSUE
bulletin E-3180 (https://www.canr.msu.edu/resources/michigan_fresh_summer_lawn_care)
If you have any questions, please feel free
to email me at <personal data hidden>.