Smoke bush how to prune

I planted one of these a couple of years ago and it is now the size I want it to be, how do I prune it to keep it the same size please ?

 

Hi, just prune back with secateurs to keep it in shape.

They will take heavy pruning eg hedgetrimmer although imo cotinus is best done judicously and frequently so it doesnt look horribly cut.

 

Thank you