Thanks, maeve.   I just needed to hear from someone who had actually pruned severely to have the nerve to do it.

Maggie, smooth hydrangea (hydrangea arborescens) is native to the eastern USA. As maeve noted, they bloom on new wood.   The blooms are a creamy white, and the cultivar I have does not have the huge blooms characteristic of Annabelle. I think smooth hydrangea is a graceful shrub, with natural variability to it's growth habit that I find very pleasing. Wild smooth hydrangea is fairly common along the woodland edges of country roads in the North Carolina mountains. It is beautiful in there in summer.

I'm guessing the hydrangeas your Dad grew were mopheads (hydrangea macrophylla.) I have them also. They are native to Japan. Lacecaps are are also h. macrophylla. I planted a couple of lace caps (tiny, in 4" pots,) the year before I moved, but couldn't stay on top of the watering during that year of the worst drought ever, so they died. I love lace caps, though, and hope to try again some day. H. macrophylla blooms on old wood. I do prune mine to keep them from getting too big for their britches, but do that by thinning out from the ground. I find them uninteresting in the garden when they get big and round - big round bush with big round flowers that flop and splay in the rain. Boring. Once established, I try to thin out a third of the old wood stems each spring. That keeps the plants at about 2 1/2 to 3' tall and keeps the over-all shape of the shrub more spikey and angular, in contrast to the blooms. It does mean fewer blooms, but I think the foliage is also lovely, and the blooms have more impact against the foliage and the shape of the shrub if the whole shrub is not covered with large balls of flowers. Except for some more recent cultivars that attempt to maintain a reddish or pinkish hue regardless of ph, the ph of the soil determines the color of the blooms. At the old house, my mop-heads were an emphatic blue. I layered them, and brought the results here to plant, next to the foundation. The ph must be mixed or neutral, because I get pink, blue and shades in between, all on the same plant here.

A friend gave me a start of an oak leaf hydrangea (h. quercifolia) last spring. I almost let it die during the dryness of late summer, but I think I rescued it. They are native to the southeast USA. I love their bark. A good understory shrub, and once established, more tolerant of dry conditions than other hydrangeas. I hope to be more attentive to this young plant in the coming year.