Macrophylla and quercifolia (oakleaf) bloom on last years
wood. Don't cut them back until after they bloom. They bloom on old
wood.

Can you tell me why my hydrangea, which I think is that type, blooms
only once every five or six or seven years? I don't prune it, but I
break off the dried sticks each spring when the rest of the plant has
leafed out and it's obvious those dry sticks will not.

When it does bloom, it's gorgeous.

Thanks. vince norris