Last week’s post was apparently pretty popular. I got a couple more emails on hydrangeas. One from LeeAnn was asking about pruning her PeeGee hydrangea. Actually, she mentioned that she has a couple of different varieties. While I can’t tell you which name the plant will have, I can give some pointers to identify what TYPE of hydrangea you may have.
I have come across several different types in my research, but some are not hardy to our state. There is the Bigleaf/Mophead/Florist type called Hydrangea macrophylla. This has large leaves and tend to have large rounded flower heads. One site said they are not hardy in Iowa, but another said that Smooth hydrangeas are. My mophead hydrangea has a bigleaf and keeps coming back every year, so this may be a case of the same name for different plants.
Hills of Snow or Sevenbark are called Hydrangea arborescens. These include Annabelle hydrangeas which are hardy in Iowa.
Pee Gee’s are Hydrangea paniculata. These are a variety that can be trimmed into tree shape and bloom on new growth. Or, at least, many do.
Oakleaf Hydrangeas are Hydrangea quercifolia. These are also hardy in Iowa.
Tea of Heaven is Hydrangea serrata and is NOT hardy in Iowa.
And then there is Climbing hydrangea, Hydrangea anomala petiolaris. Most of what I see as hardy to Iowa doesn’t list this, but I found one site that mentioned it was hardy to zone 4.
As for pruning the pee gee to look like a tree, it is amazingly hard to find detailed information on that. What I did find says that you should cut back half of the plant each year. The stems will be stronger and the blooms, though fewer, will be larger. There is some information here.
There is more information about all things hydrangea here.
Many of the hydrangeas in Iowa, especially the smooth variety grow only on new growth and the old growth is killed off in our winters. That old growth needs cut off. I usually wait until I know that there is no growth on some of the lower parts of the stems.
I cut them off and then enjoy the new growth!
When buying a hydrangea make sure you get one that is hardy to your zone and make sure you have the right light requirements. And if you have the large leaf variety, make sure you give them a LOT of water!
I hope you enjoy your hydrangeas!