Weeds

Question: This has taken over 1/4 of the patio. The roots are strong, can kill off the leaves, but not roots, Have tried “ round up” a homemade solution with salt, dish soap, and v vinegar. I live in town.

responder: Erin Hill, PhD  Replied May 16, 2023, 4:53 PM EDT
response: Is there more than one plant appearing on the roots you are able to pull up (i.e. are the plants interconnected) or is there only one shoot per root? I think this is common mallow, but I need a little more information.

responder: The Question Asker Replied May 22, 2023, 11:09 AM EDT
response: Hello,   There is only 1 plant her root. I rototill the area and it starts forming roots again, within a couple weeks, its a very aggressive weed.      Kamlyn Paksi ( she/her) Secretary  Michigan State University Extension Gratiot County 219 N. State Street, Alma, MI 48801 Phone: <personal data hidden> https://www.facebook.com/profile.php?id=<personal data hidden>5170 https://www.canr.msu.edu/gratiot/   MSU is an affirmative-action, equal-opportunity employer. Michigan State University Extension programs and material are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status.             From: ask=<personal data hidden> <ask=<personal data hidden>> On Behalf Of Ask Extension Sent: Tuesday, May 16, 2023 4:53 PM To: Paksi, Kamlyn <<personal data hidden>> Subject: Re: Weeds (#0100331)

responder: Erin Hill, PhD  Replied May 22, 2023, 11:45 AM EDT
response: These observations are consistent with common mallow (Malva neglecta). Common mallow can behave as an annual or biennial (living 1-2 years). It regenerates via seed and not rhizomes or stolons.   Manual removal can be a challenge if crowns are not completely removed, which may be the issue with it surviving tillage in your situation.   Given that you have such a prolific population, the use of herbicides may be warranted to achieve the desired level of control. The home-made herbicide described in the initial post will have only contact activity, meaning it only kills the tissues it touches. While contact herbicides can be effective, they sometimes need to be applied multiple times if all tissue is not contacted, there are ample reserves in the roots and/or the population is well established. A systemic herbicide, such as glyphosate, would be better able move within the plant to kill roots and tissues that are not initially contacted with the product. I will include some other information regarding glyphosate at the end.  The other issue is that you are likely having emergence from seed each year as the "seed bank" has been built up over time. These seeds can live for at least 100 years in the soil according the Beal Seed Experiment. To combat these from emerging each year a preemergence herbicide could be used (e.g. Preen Garden Weed Preventor, though there are others). Other tactics involve using landscape fabric to cover the soil, but it's unclear if this would be feasible on your patio.   More on glyphosate... 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. 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. for maximum effectiveness, glyphosate must be applied to annual and biennial plants when they 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).  Please let me know if you have any questions.