In our old neighborhood, this tree drove me nuts, trying to figure out what it was. We moved but still visit our old neighbors and my husband told me this tree had flowered. So, we went over and stopped at the curb and I grabbed a couple of pics.
When my son was home this past weekend I had him look at the pics. I told him it looked like a Hibiscus tree, but it didn't look like pics I had seen. My son just finished his 7th year at Michigan State University. He has a horticulture major and is working towards his PhD is plant genomics and biotechnology. He has worked in the labs there for 7 years and works with Atropa Belladonna.
He said it is a mutant and showed me a broccoli plant and said the tree has that type of mutant where the leaves are just tufts that are short and stay close to the tree, Something else of note is that it doesn't lose its leaves in the winter. In the winter it looks like this but without the flowers. It is most unusual.