Here’s the scoop on hydrangeas. All hydrangea can be divided into two categories: those that bloom on current years’ wood, and those that bloom on old wood. Nikko Blue, Endless Summer, Pink-N-Pretty, Bluebird and pink, purple, and blue varieties are all part of the macrophylla family. These varieties set their bud for next year’s flower in the stem of this year’s wood. So your blue and pink and purple hydrangea are busy right now getting ready to set their bud for next summer in the current woody stems of the shrub. Next season, when they emerge from a cold winter, the buds will actually bloom on wood from the previous season.
The hydrangeas that bloom on new wood are usually white hydrangea like Annabele, Pee Gee, Oak Leaf, and many other varieties. They put on new growth in the spring; later, in the summer, their flower buds are produced right at the end of the new growth. That’s why Anabelle and Pee Gee have such an abundance of flowers on one shrub.
Blue, pink, and purple hydrangea are beautiful in the landscape but you may have more problems with them than with the white varieties. Macrophylla hydrangea prefer partial early morning or late afternoon sun. If they are planted in full sun they require a lot of water. Sometimes you may have to water them twice in one day, even if they are established. If you plant them in too much shade they will not produce many flowers. The flower buds are produced in August and September and they have to make it through our tough winters here before they can bloom. The flower buds can be damaged by extreme weather conditions such as cold weather and harsh wind.
So now the question is, “When do you prune hydrangea?” You should prune Macrophylla hydrangea right after they are done blooming and before they have a chance to start making new flower buds. Annabelle, Pee Gee, Oak Leaf, and other hydrangea that bloom on new wood can be pruned during the late fall, winter, or early spring. My suggestion would be in early spring. Once they start growing in the spring do not do any pruning until after they are done blooming.
The Endless Summer hydrangea should be treated as a Macrophylla variety even though they bloom on old and new wood.
Winter damage to all your trees and shrubs, including hydrangea, may be prevented by using an antidessicant called Wilt-Pruf or Wilt-Stop. You apply either the concentrate or ready to spray formula in the fall and it will prevent winter damage on evergreens and deciduous plants. Stop in for more information!
I know that was a lot to absorb, but I hope it becomes useful to you. If you have any further questions, don’t hesitate to contact us at the garden center.