Q: Last year a weed appeared in my yard. I tried to keep it weeded and this year I put out Preen. None of the above did any good. It has come back with a vengeance. It is in my grass, my perennial garden, ground cover, etc. Everywhere! Please tell me what it is and how can I get rid of it!
A: I spend most of my summer weed chores fighting this pest: mulberry weed (Fatoua villosa). It is an annual weed, which means it can be prevented with the proper pre-emergent chemical. The best pre-emergent for broadleaf weeds is isoxaben (Greenlight Portrait). Apply the chemical in late March and again in mid-May. If you have a huge mulberry weed population, make a third application in early July.
Herbicides like Ortho Weed B Gon, Greenlight Wipe Out and any of the glyphosate (Roundup) products will kill mulberry weed. The key is to pull or kill the weed before it drops seed, which it can do only a few weeks after germination.