trimming leylandii

i have a HUGE leylandi and laurel hedge that i want to cut by about a third in height. somebody suggested that this would kill off the leylandii as they don't like being trimmed too harshly. is this true??

unfortunately not.

Not in the slightest. Quite the opposite to be honest. If you reduce height and cut both sides all at the same time you can stimulate a massive growth spurt that can negate the initial reduction if you don't get it under control. Whoever told you they could be killed off was proabably referring to trimming the sides. The plant won't regrow if you cut the sides back too harshly to old wood.

Feel free to crack on and get the top third off now. Once finished the trunks should be lower than tips of the lateral branches, you're aiming to see a nice 'valley' in the middle of the top of the hedge if you're stood on a ladder at one end looking down the run. Some people go saw crazy and end up with a horrible result so if you can, cut above your finished desired height. You can always cut more off later but you can't glue it back on....

best thing with leylandii is to trim them to 6" below the ground.

Every gardener's best friend. Clear all wildlife away from the area first obviously

thanks all, great advice will go right ahead and do the deed!

advice is right in terms of ridding them, however theres nothing wrong with leylandii used and managed in the correct circumstances