It's a weed, but I don't know what it is called. I've been trying to get rid of it for years.

It's called dayflower.

Yes, dayflower... isn't this a type of spiderwort?

:)
Dee

Many opinions of Asiatic Dayflower, Commelina communis, scroll down to gardener's notes.

Claire

Thanks all - We find it really easy to control. And it's in a transition area for us. To wit: We dug up a pair of 50-year-old hydrangeas in April. I mean we hacked them out of the ground like a dog after a bone. And then we threw the resulting 6 of them (3 clumps from each) into shallow holes, filled in, and watered. My neighbor watched the atrocities from over the fence and gave them 25% chance of surviving. Well ... thanks to our rotten weather and non-existent "June," they have not just survived, but they are specimens. No flowers this year as we gave them the type of haircuts that should have been given the Wall Street crowd last October. But next year will be one for the records, I predict. And in this little area, we placed 2 of them, and have filled in with volunteer cosmos and this little Day flower.