What is the tall shrub that has large double flowers that change in color from white to pink and how do I grow it?

You are describing the shrub that is nicknamed Confederate Rose (Hibiscus mutabilis). Confederate Rose is native to southern China and has been popular  in our area for several generations. Give it a sunny location, use 5-4-7 Azalea/Camellia fertilizer in the Spring and Summer ,water during long dry spells and watch for Whiteflies. This shrub loses all of its leaves in the winter. Confederate Rose can grow over 15 feet tall if not pruned.

Visit our Year Round Color photo album for a good picture of a Confederate Rose bloom.