whats the name of the flower?
From your picture attached you have a variety of a pink Rose of Sharon, Hibiscus syriacus. This is a lovely shrub but a heavy feeder. Give it organic fertilizer or a fertilizer high in phosphorus and low in nitrogen. The more nitrogen the more insects and leaves instead of flowers. I'm attaching a publication on Rose of Sharon because even though I do not know the variety pictured, they would all be taken care of the same way. http://www.garden.org/plantguide/?q=show&id=2102
Let us know if we can help you further. A