Marshland Darter on lavender in our garden

It's a weed, isn't it? 2010-007-18: I have no idea what it is or who planted it. It is growing outside our fence, on the gravel parking spot, next to the telephone pole at the corner of our garden. But once a year it has beautiful flowers. Thanks, Kara: Sure does look like Hibiscus Syriacus (Rose of Sharon). Many thanks for the tip. The comments on yesterday's shot were amazing. Many thanks to all!. Have a blessed Sunday.