Question
I have 5 high very mature Cyprus Leyland conifers over 20 years old and closely side by side that I would like to prune from about a 12 metre height to form a hedge about 3 metres tall. Can I prune them this low (even by making a number of smaller prunes over a couple of years). After pruning will new growth appear all up the trunk or just from out of the top. After pruning would they need some plant food ?

Answer
If you are saying that the lower trunk has no branches now and if you prune the tree to 3 meters will new branches sprout?? I do not think you will have much luck getting the branches to sprout on the lower trunk. The older bark has formed and there would be no buds to sprout from. I think you would end up with a short tree with no branches on the lower trunk. A picture would help but that would be my guess without seeing the tree as it is now. Sorry!