That would be Venice Mallow or Hibiscus trionum.

tj

Here is a link that might be useful: Venice Mallow

Thanks tj!

I did some reading in the Plant files on Dave's Garden site, and aparantly, it's a potentially invasive weed, according to some gardeners' notes. I don't think I'll let it reseed in my garden, even though it's very pretty.

A few comments from other gardeners on Dave's site:

1. I can't believe this weed is even listed here. It is terrible!
2. The flowers aren't even that showy and they aren't open all that long. Perhaps around a half hour early in the morning and after that all you get to see is scraggly foliage sprawled out over the ground. Good thing is that it is an annual so if you keep pulling it up, sooner or later you'll beat back the seed bank.
3. ...they invaded like Atilla the Hun.
4. This plant needs to be tacked up on the Post Office Bulletin Board. Another good thing I can say on the plants behalf is, the tap root is easy to pull out.
5. Kill them early and kill them often would be my suggestion. When you think of this plant, think INVASIVE, such as in "Invasion of the Body Snatchers".

Again, thanks for the ID, tj.
I'm going to go pull it right now!

Julie

Over the years, I've had many surprise plants that arrive in mulch or hauled in soil. A creeping blue speedwell was about the prettiest, horse tail the oddest, and burdock and thistles the worst. My mantra is 'If in doubt, yank it out'. Pondy

My mantra is 'If in doubt, yank it out'.
Good policy to follow, Pondy!

Julie