I have a supplementary question to your informative answer on pruning hydrangea tree. How do I keep it just about 3-4 feet tall, but still let it flower.
As mentioned in our previous answer, this type of hydrangea produces flowers on branches that are produced the same spring (known as new wood). That means you can cut the branches back in fall, winter or in early spring. I find it’s easiest to do in spring, when you can see the new buds developing. Cut each branch back to just above a set of buds.If you want the crown of the tree to stay compact, then cut branches back closer to the main trunk (but not all the way). Once you have pruned back your shrub to your desired size,(2-3 bud unions) outside of removing any damaged or dead branches pruning is done for the growing season. New growth will begin to form from the bud unions and flowers will begin to develop through out the season at the tips of strong branches. If you continuously prune your shrub through out the growing season to maintain a height of 3-4ft you will be cutting off this years flowers.
Hope this helps.