Question
My mother lives in northern OH (zone 4).  She has several hydrangeas which did not bloom for the past summer.  Should she cut them back to encourage blooms for next summer season?  All of the plants are approximately 4 years old.

Answer
Paula,
You don't mention what type of hydrangeas your mother planted - if they are white flowering Pee Gee's or Annabelles she doesn't have to do anything - if they are not in deep shade they will bloom on new growth next season.  If she's planted blue flowering hydrangeas, they all bloom on old growth, and some of the new varieties such as Endless summer bloom on both new and old growth.  If she bought a standard blue/pink variety it will is not likely to bloom because it gets cold enough in Ohio to freeze the flower buds that formed the previous summer. If it goes below zero, these hydrangeas won't bloom, but will die to the ground every winter and grow back from the roots, but never form flowers.

Her best chance is with Endless Summer, which blooms on new growth as well as old, so if it dies to the ground it should still form some flowers on the new stems that come from the roots the following summer.  It should be planted in part sun, and not get any fertlizer from the lawn (high in nitrogen).
Her zone 4 is marginal for even this plant, however...I think that Endless SUmmer might be rated a zone 5 plant.  If she wants to try and build a cage around it and fill that cage with leaves and/or straw, and then cover just the top with plastic so that the hay/leaves doesn't get wet (but leave the sides open to the air) and then uncover the plant in early April, that would be her best shot at getting flowers for next year.

Becuase the flowers form the previous summer you should NEVER cut the canes down at any time of the year - even varieties like Endless Summer.  If the canes are dead after the winter, of course, she can cut them off.

Your mother should regard this plant as an experiment and a challange, not a sure thing!  I wish her all the best with it!
C.L.