Culture and Growth Rate

• Rose of Sharon shrubs have a moderate growth rate, according to Ohio State University. They grow best in moist, well-drained soil high in organic matter, in sun or light shade. Providing the plant with its optimum growing conditions will encourage strong, rapid growth.
  
  

Spring Growth

• Hibiscus syriacus is a heat-loving plant, so it's slow to leaf out in the spring. Don't despair if your shrub is still leafless while other plants are already covered in new leaves. Once it does break dormancy, the plant will grow rapidly.
  
  

Pruning

• Rose of Sharon blooms on new wood, so take advantage of its late dormancy to prune the shrub for shape and size. The University of Connecticut recommends annual pruning to increase plant vigor and encourage larger flowers.