Hi. I'm wondering why my hydrangea blooms have no or very few petals. The blooms emerged weeks ago and bees have been swarming them. They appear to have tiny buds but only a couple petals around the edges. Neighbors' plants are in full bloom.

Welcome to NGA, noanker. It seems to be perfectly normal. That species of hydrangea produces lacecap form blooms, in which the fertile blooms are in the middle and a few white sterile sepals (what you call petals) grow in the outer periphery of the bloom. It is sometimes called wild hydrangea (hydrangea arborescens) although there are named cultivars like Haas Halo, Radiata, White Dome, etc. The blooms produce a fragrance that attracts pollinators. Enjoy!