When should I prune my Hydranea Incrediball?
Certified GKH Gardening Expert
It is advised to prune during dormancy, which may be different in your country than here in the US. Between this time, and early Spring is the best time.
Since your hydrangea is H. arborescens, (just like the Annabelle) it will flower from new growth. This means that it can be pruned anytime as long as it is not blooming, or budding for blooms. Some people in prune them in Summer, directly after flowering, so the guidelines are simply for the absolute best time to prune.
This article will offer information on pruning different hydrangea types: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/prune-hydrangea-bushes-hydrangea-pruning-instructions.htm