The name is oxalis and yes, they do spring up everywhere. Pull them up as much as you can because they will reproduce quickly. There is not too much you can do but keep pulling as fast as you can. I have the white oxalis contained in a pot and it blooms year round. However, the pink and lavender that grows all over my yard is a real nuisance.
I believe there is a fertilizer that will kill it--yes, a fertilizer. Ask at the garden center or e-mail your county agent and ask.

Well I like the pink ones. I say enjoy them cause you are going to be digging like mad to attempt to get them gone. They form a small bulb, pea size, and if you leave one you will have more plants in no time. Think of it this way ... atleast its a small sized plant and they are pretty in bloom.
I have the burgundy leaved one in a pot and love it.
Mike

Hey ya'll,
You can't live in south LA and not do battle with oxalis.
I've found a product that helps. It's preen. It's usually available at Walmart, Lowes, or The Home Depot. I buy the large container and do battle each spring and again in the fall. Dig up as much of the root and bulbs as possible and then sprinkle the preen. Good luck.

Granny Brenda
Harvey, LA

Oxalis is an interesting example of a plant that has evolved to co-exist with people. The Native Americans collected the tubers to eat. If you examine them when you pull them up, you will find at the top of the tuber many tiny white babies about the size of rice. When you pull them up these little guys scatter themselves to increase for next year. One year when I was new here I decided to get rid of the few clumps I had and really worked at it, trying to get all the little ones too. The next year I had THOUSANDS more. I find if I don't try to pull the whole thing but just get the leaves that they are slowly shrinking as they can't gather 'food'. May try the Preen tho'--sounds good.

Ortho-Weed-B-Gon for lawns might help if you don't have St augstine.Scots lawn and weed control be sure and check grass type do not use ether on or near flowers you won't to keep.be careful hope this helps Jim