Question

weeds  

weed   Hi Susan, I have an unknown weed invading my back yard. I live in Virginia and next to a pond and this weed is originating from this pond area. I've used Ortho Weed-B-Gon but it doesn't have any affect on it.

I'm enclosing a pic. Thanks for your help.

Answer

common mallow   Hi John,

This looks like common Mallow (malva neglecta). If I'm right, I'm afraid you're in for some work here.  I'm going to include a link to a Mallow management guide at the end of my answer.  It is resistant to most all herbicides.  Even Round-up doesn't kill it.  24D might slow it down a little.  It's too short for a lawn mower, and has roots that go to another zip code.  It looks like you have it in such an extensive area, that hand digging is impractical.  Even if you spent thousands of dollars digging it out, replacing the dirt, and re-sodding, it would probably be back in less than a year. DO take a sample of the plant (and some of your lawn grass for id) to your local nurseryman or county co-op extension agent for confirmation of my identification, and any suggestions they may have.

I have an unusual suggestion.  Stop fertilizing that area of the lawn and start eating it.  It tastes pretty good, whether raw or cooked.  The roots were an ingredient in marshmallows.  It can be used as a substitute for rennet to make cheese.  It's used in all kinds of skin care products.

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74127.html

Good luck, John!
Susan