How do I prune hydrangeas both to shape them and to encourage blooming?
I have both the old-fashioned "snowball bush" plant with white blooms, turning green and then dry brown. I also have the new varieties (Endless Summer) that bloom pink or blue all summer long. The branches on both varieties are white and somewhat hollow appearing now. How do I prune these to control the shrub shape and to encourage as much blooming as possible?
Marion County Iowa
The smooth hydrangea (Hydrangea arborescens) grows 4 to 5 feet tall. Smooth hydrangeas bloom on new growth. Plants produce white flowers in flat to roundish clusters in late spring and summer. ‘Annabelle’ is a widely grown cultivar. Smooth hydrangeas can be pruned back to the ground in late March or early April.
Bigleaf hydrangea (Hydrangea macrophylla) cultivars, such as 'Endless Summer' bloom on the previous year’s growth and new growth. After a mild winter, these plants bloom in early summer on the previous year's growth and late summer on the current year's growth. After a cold winter, 'Endless Summer' and similar cultivars die back to ground level but bloom in late summer on the current year's growth.
For maximum bloom, wait until the shrubs begin to leaf out before pruning bigleaf hydrangeas. When growth appears, prune out all dead wood.