Agree with floral. First, it is definitely a bigleaf hydrangea, Hydrangea macrophylla. And you want to be careful about cutting back or "evening out" with these as you run the risk of cutting off latent flower buds that were formed the previous summer. Removing dead wood is fine and in our area, bigleaf hydrangea are leafing or already leafed out, so dead wood - branches with no buds - should be readily apparent. But it won't hurt to wait some if you are unsure. And I have never encountered the practice of "leveling or evening out" a hydrangea!! Hydrangeas are living plants and they grow the way they want to grow - some branches shorter and some branches longer. Hedging them or confining them to a smaller than natural form will only reduce the amount of flowering potential they have, at least with any macs. Most hydrangea growers recommend keeping pruning of these to a minimum - just the deadheading of old blossoms and the removal of dead/non-viable stems - so that means siting where they can be allowed to grow to size or if needs must, doing a wholesale chop every now and again to reduce size. But this will remove any potential for flowers for that season in most cases. Not a plant you want to be dong much trimming or pruning on if you are growing it for its summer flowers :-)

Thanks! One of mine had a dead flower. I'm pretty sure you're right and they're bigleaf mopheads, assuming they're all the same type. We're right on the water so the hottest we ever get is mid 80s. I put three in a dryer area that gets sun til about 1pm at the latest and the other three in a moist area that gets sun til 3pm. Both are on slopes so they should drain well. Hopefully they'll be happy there.

It won't survive very long as a houseplant, either. Plants that grow outdoors in temperate areas (even though not fully hardy) are not well adapted to indoor conditions - too little light, too low humidity, etc. They'll survive and struggle on with reasonable care but they won't thrive and often just decline. Better to grow it as a containerized plant - in a properly sized container - outside, only bringing it in for winter protection when it goes dormant for the winter. And by "in" I mean somewhere where it remains cold but not freezing - a garage, cellar or unheated basement.

Looks like one of Ryoji Irie's hybrids. Probably one of the You-Me series. Can't venture to guess which exact one, though. ;)