Hills-of-Snow or Sevenbark Hydrangea (H. arborescens ‘Grandiflora’) has dull, white flowers that are not as showy as we’ve come to expect from hydrangeas. It is a rounded shrub with leaves that are somewhat rounded with a pointed end and paler on the lower surface than on the top. Hills-of-Snow does not usually have trouble blooming because its flowers are set only on new growth. This is a good thing because it is very susceptible to winter injury and is often killed back to the ground in colder areas. If winter injury is not that bad, you can prune slightly by removing some branches to the ground and cutting others back to shape the plant.
'Annabelle' is a very popular H. arborescens with conical flowerheads that are considerably larger than ‘Grandiflora’. Its leaves are fuzzy gray on the lower surface.
Oakleaf Hydrangea (H. quercifolia) is easily recognized by its oakleaf shaped foliage. Since its major attraction is its foliage, loss of bloom is less disappointing than in other varieties. Oakleaf hydrangea also blooms on new season growth and can be pruned in late winter or early spring, while dormant, to remove dead wood. If it has experienced winter dieback, prune back to below the point of injury.