If this shrub behaves as advertised, you do not need to winter protect it in your zone but, I would still maintain 3-4" of mulch up to the drip line or further away. Incrediball is supposed to be hardy to Zone 4.

Normally, you would not need to prune in Spring except that, in your case, some stems may dry out during winter. If they do not return by late May, I would consider them dry & dead; so cut them.

You can fertilize it once a year in June with 1/4 of a cup of manure, compost or cottonseed meal. You can also use a general-purpose slow-release chemical fertilizer like Osmocote but follow the directions on the label. You can also apply weak fertilizers like coffee grounds, liquid seaweed or liquid fish during the growgin season. Do stop all forms of fertilizers by July to make sure that the plant starts going dormant in the Fal. And keep lawn fertilizers pellets away from under the hydrangea after July; they contain a lot of nitrogen and high nitrogen fertilizers keep hydrangeas in growth mode.

Thanks Luis! Great information, one quick f/u - what's the drip line?

It is a term that indicates an imaginary line where the water falls if you watered the leaves of the shrub. The water would drip off the leaves into the ground and mark a "drip line". When watering, you usually want to water the soil from the main trunk or crown of a plant thru the drip line. When adding mulch, you do the same.