Eventually, you will get more stems to grow from the crown but it is slow... it's just not a process that happens in one growing season or a process that you can force to force new branches. Yes, you may well have to eventually prune that one, but only to make it "match" the length of the stems that will be growing in the future. But I would not bother pruning it now. When you have more growth (stems/branches) then I would consider pruning it a bit or even pruning it off completely. btw, they do look nice!

Yes, all hydrangeas are caning shrubs, meaning they produce new stems directly from the root crown. While the cuttings (?) above are too young to demonstrate this characteristic, in time you will get additional stem growth from the root crown.

So I agree, no need to prune now. You just need to be a bit more patient and the plant will begin to branch out all on its own.

gardengal48 (PNW Z8/9) Well that's weird, Is there maybe a tree variety? The reason I was so concerned about this, was because these cuttings were taken from a tree. The tree never produced growth from the root crown, and if it did, that was many years ago, before the crown crew upwards. This one started branching out about 4ft off the ground, and was never pruned. Maybe they grow like oaks and once they get older the root grown starts growing upwards producing a trunk?

Have a look at this one here as an example.

FastInk, Tree hydrangeas are created by pruning and training, that isn't their natural form. The one in your photo is a Hydrangea paniculata and started like any similar large hydrangea and was trained to that form.

NHBabs, I figured that particular one could of been, however, mine was never pruned or trained to appear that way, and it still took on the tree shape. I used that picture as an example to indicate the form of which my hydrangea is.