That depends on what type of hydrangea it is. If it is of the type that blooms on 2 year old wood then it shouldn’t be pruned since that will remove this years flowering potential. If it is a type that blooms on new growth then it could be pruned away without ruining the flowering cycle. If you are in doubt, leave it to see if it flowers. HERE’S A LINK that can help you figure out what you have and how to prune it.