Did you ever really look closely at a hydrangea blossom? What we think of as a “flower ” are really primarily bracts surrounding innocuous little florets in the center of the bloom repeated hundreds of times over and over to make up that lovely “flower head.”
It’s easy to see on this lace cap flower here at the bottom. The actual “flowering” particularly of the plant is in the center of the entire blossom, surrounded by the sterile bracts.
Here’s on this smooth hydrangea, almost all that’s visible are the bracts. The fertile flowers are just about hidden below them. You can just about see little white starbursts–those are the flowers.
On this big leaf type hydrangea, the flowers are located in the center of the bracts. None has matured to the point of being available to pollinators.
So that’s a brief overview of hydrangeas. Despite the fact that they are not native, pollinators in my yard enjoy them. But there are lots of natives to draw the pollinators to the yard and to keep them happy.