On Friday I talked about hydrangea macrophylla–big leaf hydrangea–without ever specifically calling them by name. Today I want to talk about some of the other types of hydrangeas, all of which bloom on “new” wood.
Maybe I need to make the “old wood” versus “new wood” distinction clear first though since we’re not all born with this knowledge.
If something blooms on old wood, that means that right now, this summer, 2019, it is setting its buds for bloom next year, in 2020. So if you were to prune it in the spring, 2020, or, like in my climate, if a hard freeze (or late snow) comes as the buds are unfurling and kills them, you lose the bloom for the year.
If something blooms on new wood, that means that the buds are formed in the same year that the plant blooms. The buds are formed in 2019 and the plant blooms in 2019. So you can prune in the spring without losing your bloom, and late freezes or snows are not a problem.
You can see why these hydrangeas that I mentioned in my prior post–the ones that bloom on old and new wood–have been game changers for us here in the “frozen north.” But as weather becomes less predictable, they will be more useful to more people, I think.
Several types of hydrangeas make the distinction a non-issue. These include the “Annabelle” types, and their hybrids (hydrangea arborescens), tardiva types, paniculata grandiflora types and their hybrids–there are a lot of choices.
The hedge of pink hydrangeas in the photo above is the original Invincible Spirit hydrangea, a type of hydrangea arborescens. It is about as easy care as it gets. All I ever have to do is to remove the spent flowers–and periodically I trim it back a little. That’s it.
But the beauty of these types of plants is that if you wanted to, you could cut them back hard in the spring, or, if there was a hard freeze, or heavy animal browse, it wouldn’t matter. They still bloom because they bloom on new wood.
On Friday I will have photos of some of the other types of hydrangeas that bloom on new wood and talk a little about them.
This is why conventional hydrangeas are not easy to prune in winter. It would be easier if they could be pruned like roses! Well, I still won’t give up my old ones for new types.
You see, you are in a climate where you don’t have to. I have one where the last time I saw a bloom was 2013–I looked back through my photos to be sure.
When it was smaller, I used to wrap it with burlap. That’s probably why it bloomed in 2013. Now it’s just too big to do that with. So I have a nice leafy shrub every year. And I never prune at all. It’s just my winter killing the buds.