Hydrangeas can be broken down into two main types, those that bloom on Old Wood and those that bloom on New Wood. The prunning methods are drastically different for each of the two types.
1.) Hydrangeas that Bloom on Old Wood - set their flower buds for the next year the previous summer.
2.) Hydrangeas that Bloom on New Wood - set their flowering buds on the current seasons growth.
1.) Blooms on Old Wood:
- Old Wood consists of stems that have been on the plant since the summer before the current season.
- These Hydranges set their flower buds for the next year in August, September or October.
1.) All dead wood should be removed every year. This can be done at anytime of the year.
2.) After the plant is 5 or more years old, remove 1/3 of the oldest canes, by cutting them down to the ground, to rejuvenate the plant. This can be done in early spring or at the end of the summer.
3.) Pruning plants to control size should be done in June or July before the plant starts to set flowering buds for the following summer.
4.) Deadheading = removal of old flower heads. Deadheading can be preformed anytime of the year.
2.) Blooms on New Wood:
- New Wood consists of stems that have developed on the plant during the current season
- These Hydrangeas set their flower buds during the spring and summer of the current season. These flower buds open the same season that they are produced.
Annabelle Hydrangeas- bloom in the spring and early summer
- 1. cut entire shrub back to a few inches above the ground. Beware, that this method will cause the new stems to be thin, which may lead to flopping under the weight of the large flower heads.
- 2. cut shrub back by 1/2 and remove 1/3 of the oldest canes each year. This will allow the remaining branches to thicken up and reduce the need for staking once the shrub is in full flower.
Hydrangea Paniculatas - bloom in summer and fall
Endless Summer Hydrangea - bloom late spring, summer and fall