Answer: Based on your zip code, you are gardening in zone 5A or the coldest part of zone 5. Depending on your microclimate, it could be as cold as zone 4. The common bigleaf hydrangea (Hydrangea macrophylla) will possibly be root hardy in such a cold climate but most likely would not be able to bloom. The reason for this is that these hydrangeas bloom on old wood that grew the year before. If the winter cold kills the stems, they can't bloom the following summer. For the same reason, pruning in fall or spring will prevent flowering. (The only "safe" time to prune would be summer right after it blooms.)
If you want to have a blooming hydrangea, a better choice would be the extremely winter hardy white flowered Hydrangea arborescens such as "Annabelle" which blooms on new wood, meaning new growth of the season. Or, you could consider the larger growing woody shrub PeeGee hydrangea (Hydrangea paniculata) which is also more winter hardy and blooms on new wood as well.
In general, the hydrangeas will bloom best in rich soil that is evenly moist yet well drained, and in all morning sun or very bright dappled light all day. (The PeeGee types can handle more sun and will do fine in sun all day.)
I hope this helps.
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