Answer: When hydrangeas fail to bloom it is usually because they are freezing down to soil level each winter. Hydrangea macrophylla (big leaf hydrangea) blooms on new shoots that develop on old wood. Pruning off all the old wood, or having all the old wood die back during winter, will keep your plants from blooming no matter how well you take care of them the rest of the year. Some of the newer hydrangea cultivars (especially 'Endless Summer') bloom on both old and new wood so it doesn't matter if these plants freeze all the way down to the ground. Rather than frustrate yourself, why not replace your old hydrangeas with those that bloom on both old and new wood?
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