If it looks like clover, grows from a central point and has tiny yellow flowers -look out! The seeds form a burr and the burrs are nasty. I have two dogs and they have carried it on their fur into my back yard and along our sidewalk. Corn gluten did not stop them this year.

I have been waging war on that same clover stuff bedford. Those stickers are gnarly! I innocently thought that it was clover and let it get a strong foothold, then discovered the burs. It's easier to get out after a rain.

Thanks Bedford, but it's not clover-like and it has little white flowers. I think one year I let it go, thinking it looked pretty...which was a mistake, obviously!

Post pics please!

Next time I find a clump big enough to photograph, I'll take a picture! I didn't think to take pictures before I started pulling it. I was hoping that it was common enough that people would recognize it by description.

The only weed I can think of with somewhat sword shaped leaves and spreads by rhizomes, as well as seeds, is what's commonly called 'Widow's tears' also known as Spiderwort (of which there are good garden cultivars), but their blooms are blue; although some are very light blue. Could that be it? If so I've been temped to leave them in the garden too, but they do want to take over.

Here is a link that might be useful: Could it be these? Google images ...