the answer is prune down to the ground in january...and i mean right down , dont worry about leaving any old wood showing...any later and you can t avoid hitting new growth...that means you can chop off any bits you like now....this treatment by the way also works for that Fuchsia with the large showy flowers that is totally hardy called " Mrs Popple "....every other year is just as good for the Fuchsia...or even every 3rd year...if you had 3 of them you could rotate the hights over time...this kind of " down to the ground " pruning works if you re prepared to feed the things as and when...you get very natural looking shapes ...be prepared to romove completly any new leading stems that cross or grow inward...i love this pruning method...have a go...!!!