I think I have shrubs and plants like Berberis,Rhodododendron,Pieris,Hydranga,cotoneaster,Ulex, Garrya,Romneya,Rubus and many more but what I would realy like to know is how hard can plants and shrubs be cut back as a lot of mine are overgrown and I would like to get the garden back into shape.
In general, most shrubs will re-sprout if cut back hard in spring. But some will not, such as broom although Spanish broom will!
If they don’t recover, the space can be given to something else.
 More at:   https://gardenie.wpengine.com/gerrycategory/pruning/?id=5415
And by the way …. never try to cut a shrub with a chainsaw as it is highly dangerous, the chain can jump out of the guidebar and break.