Types

• Most hydrangeas are deciduous shrubs. Bigleaf hydrangeas are a well-known deciduous variety. Some species, such as oakleaf hydrangeas, develop colorful foliage before losing their leaves in the fall.
  
  

Location

• Some hydrangeas perform as evergreens in USDA hardiness zones 7 and higher, keeping their leaves throughout the year. An example is the blue evergreen hydrangea, also known as Chinese quinine. This plant performs as a deciduous plant in more northern regions however.
  
  

Considerations

• If you want your hydrangeas to keep their leaves all year, plant them in as ideal a location as possible. Providing protection from the cold, northern wind throughout the winter sometimes helps this plant retain its leaves. Bigleaf hydrangeas are most sensitive to low winter temperatures and will not survive in areas colder than USDA hardiness zone 6. This cold-sensitive shrub grows as an evergreen only in extremely warm climates, such as southern Florida.