Rose of Sharon are in the hibiscus family of flowers (as are the mallow flowers), it is a common name that actually gets applied to several plants. I found these plants growing in someones garden.
It was an overcast, rainy day, which washes out the color a bit, but made for some great water droplets on the petals.
The flowers are large, more than 4 inches in diameter.
All photos taken by me on a Pixel 2