02/24/2023
Foliage growth on garden hydrangeas (Hydrangea macrophylla) is commencing. Wait a few weeks after leafout and prune out any dead wood. Dead wood will likely be considerable this spring on these hydrangea types due to the December 22-27 cold spell. Fertilize soon with a slow release ornamental / landscape fertilizer - Osmocote, Fertilome Gardener's Special, Fertilome Tree and Shrub Food, etc. Do not do a height reduction pruning on these - on most garden hydrangeas flower buds for this year were set last year (late summer, fall).
Keep in mind that in many areas of the South, you may not get good garden hydrangea bloom this year since the cold weather very likely damaged the reproductive buds - it was very warm 2 weeks prior to the freeze event and wind dessicated many plants. A "flash freeze" occurred.
Some garden hydrangeas - such as the Endless Summer varieties that bloom on new wood - will likely bloom this year with good late winter, early spring care. This picture is in Louisiana.