Shirley and I were visiting local gardener Bill Wulffâ€™s garden and a question came up on how, or if, he should prune his oakleaf hydrangea.
Well I thought I would do some research before I gave my opinion. I do suggest, when in doubt, check a topic out on the web or do some research at the library, if anyone uses those anymore. I do have a resource that I think is great–the University of Illinois Extension Service: http://web.extension.uiuc.edu.
As I thought, the flowers are produced on last yearâ€™s growth, so if you cut the heck out of the plant in spring you will not get many flowers. Itâ€™s easy to say. but tricky to determine, which branches are this yearâ€™s or last yearâ€™s growth, but if you wait until early fall after the blooms have faded you can tell which branches are done and prune away if the shrub needs to be shaped or its size kept under control, because it can grow up to fifteen feet.
The oakleaf hydrangea, if it is planted in the right spot and has plenty of room, doesnâ€™t have to be pruned at all. just deadhead the flowers and cut out the dead wood if needed.
If it is totally out of control and you want to start over, it can be cut to the ground.
It is one of our favorite plants.