Does it close up at night? If so, I think I have them in my garden too. The name is on the tip of my tongue, argh. Starts with an "O"???

It's a Venice Mallow - usually considered a weed. It's on a number of state noxious weed lists. But some folks like it. Below is a link to the Dave's Garden listing.

Here is a link that might be useful: Venice Mallow or

Thanks! That's it alright.

And this from the Dave's Garden comments fits what happened here:

###The seeds came be dormant for 50 years the are where these started to grow had not been touched in 23 years so crunch those numbers. All it took was the rain and a little sun and they invaded like Atilla the Hun. ###

(Except I think there is only that one so far)

And although it is a beautiful flower, sounds like it might not be worth it. I'll have to think it over.

Thanks again.