Q: I recently purchased some hydrangeas and planted them in thirty gallon containers. Are the containers big enough to allow the hydrangeas to survive the winter?
A: Your container is a good size for hydrangeas that can be kept four feet high and four feet wide, so adjust your pruning to accomplish those dimensions. If you let the shrubs get much bigger, their water needs in summer will outpace the ability of their confined root system to supply hydration. There should be no problem with winter freezing.