Why doesn't my three-year-old hydrangea bloom?

FAQ
Question: 

Why doesn't my three-year-old hydrangea bloom?

Answer: 

Many varieties of bigleaf hydrangea (Hydrangea macrophylla), such as 'Forever Pink' and 'Nikko Blue,' usually do not bloom in Iowa. The bigleaf hydrangea blooms on the previous season's growth. Unfortunately, in Iowa, the plants often die back to the ground in winter. The plants grow back vigorously in spring, but don't bloom since the previous season's growth has been destroyed.  Newer bigleaf hydrangea cultivars, such as 'Endless Summer,' are much better choices for Iowa gardens as they bloom on both old and new growth.

The white flowering hydrangeas (Hydrangea arborescens and Hydrangea paniculata) commonly grown in Iowa bloom on new growth. They are relatively trouble-free. Once established in the landscape, they should bloom every year.