not sure without a close-up photo, but it looks like weeds.

Looks like purslane to me. Broadleaf weed killer can kill it in the spring. Clover attracts bees so be sure that's not a problem for you before you plant clover.

I think it might be pepper grass. If so, it will make a tiny white flower on top that will seed like crazy. Each plant is a little clump and easy to pull out. Definitely not purslane.

This looks very much like chickweed: http://www.foragingtexas.com/2008/08/chickweed.htm

If it is, it's kind of pretty and edible with delicate little white flowers. Mine seems to dry up mid-summer though, not to return til the next year. I need to find more chickweed recipes!

Nice patch of weeds there .... definitely not clover.