I have one Hydrangeas , dont know the name but every year it only has two blooms. This year one is pink and the other one is purple. I have an annabell that has probably has 150 blooms on it.
Hydrangeas
What zone are you in? I could be wrong but I thought Iowa is zone 5-6-ish, and your hydrangeas sounds like an H. macrophylla variety. Most H. macrophylla's bloom on old wood, so in colder zones if you don't protect them for the winter they will bloom poorly or not at all because many of the buds will get frozen off during the winter. If you don't want to go to the trouble of protecting them, look for ones in the Endless Summer or Forever and Ever series, those will bloom on new as well as old wood so you'll get some blooms even without protecting it. Or if I'm mistaken and your zone is warmer than I thought (or you're already protecting them for the winter), pruning too late in the year can have the same effect since you cut off the part that would have flowered the following year.