Oxalis hedysaroides I believe.

Maybe the sage gives off a chemical that keeps it away. I read about a plant that did that and it prevented other plants from growing near it. I cannot remember which plant that was now, but it was an interesting article. My Russian Sage was over run by stilt grass this year. Maybe it just keeps wood sorrel away. Come to think of it, there wasn't any wood sorrel there when I weeded out the grass. Hmmmm. Some one / some company has made a weed preventor from the chemical that plant gave out, but I cannot remember the name of it either. Maybe someone else knows.

Thanks, eaga and floral_uk. This pest is everywhere, and I just read that it can regrow from even pieces of stem. More seriously, I read that it can spread viruses to crops like tomatoes. Here is an interesting link. Well, no more tossing it into the uncooked compost pile. http://agron-www.agron.iastate.edu/~weeds/weedbiollibrary/517%20student%20pages/2000/Galinsogad..htm

Thank you for your reply. I think mine isn't quite as "stringey" as sarmentosum. I've seen that, and mine seems different. And the leaves seem kind of more roundish. Doesn't this drive you nuts??? There are so many kinds of sedum.