Yep....hardy hibiscus.....aren't they amazing?
Linda C

And they are not annuals....but perennials. Die to the ground and don't emerge until very late....sometimes not until June.....and then just shoot up.
Linda C

If you are in zone 5, as am I, then I gotta get me some of those!

Hi,
My guess would be Lavatera.
I think it is also called Rose Mallow or Tree mallow.
The blooms are very much like hibiscus blooms.
It is an annual but will reseed if seeds fall to the ground.
Char

My guess is hardy hibiscus, and not a lavatera. They grow by the million around here in tidal freshwater marshes and sometimes along the edges of ponds - a wetland on my way home for work features about 20 acres of the stuff and is quite something when these plants are in full shout. They are perennial here in south Jersey and reseed like mad. I've grown them for 20 plus years. They escaped from my garden and have been slowly advancing northward up a roadside drainage ditch. Their seedheads are kind of nice too, we usually leave a few stalks standing for winter interest.