How to prune a Hydrangea paniculata 

Hi! Many Living Creations varieties have huge flowers that get heavy from rain. But under normal conditions, they will not break. Soon after the rain, downward bending branches and flowers will soon come back up. If they don't, something unusual is going on. Are you sure you have a Living Creations variety? Are you possibly using (too) much fertiliser with very high Nitrogen? In the latter case, it's better to fertilise organically with more Potassium.