My 5 yr old Clematis (Armandi ?) is groing a bit too well on my back garden wall (South facing and approx 8 ft tall).I planted it to hide the unsightly plain block wall. I “pruned” it earlier this Spring ( ie I took the clippers to it because it had grown so rampantly and it was too large and time consuming to prune with a pruning shears. It has not flowered this year, understandibly. Must I prune only with a pruners? and when should I tidy it up again ?