I have a wide 5 leylandi tree hedge that gets away if I dont keep on top of it. In the last 5 years, I must of had a least 20ft lopped off it in two or three go's. Ive learnt my lesson and have it clipped and pruned twice a year. I have two glorious springtime clemetis growing through it
these dont seem to suffer with all the chopping and pruning. Saying that they do migrate to my neighbours side of the hedge as they catch more sun than myself!