By Phat
United Kingdom 
i have annually (13yrs)trimmed my side and top of a 300m leylandii/conifer hedge in september, the past two years it has developed brown/dead patches due to severe winters but is still very saveable. i have been advised not to trim in september but to do it in spring. Is this true? Are there other alternatives, once per year.
4 Jul, 2011
Answers
A tree nurseryman friend recommends cutting in July/August.
5 Jul, 2011
thank you, will cut july/august
13 Jul, 2011
Hope it works for you Phat
13 Jul, 2011
Previous question
Alot of Leyandii suffered badly last winter. One of the problems was that we had a mild period followed by extreme cold and snow. Plants did not have the chance to harden up properly. I do think this was a problem with Autumn cut Leyandii, they had not had the chance to recover from the shock of their trim and the cut neds were vulnerable.
I don't know, but I see no reason why they couldn't be trimmed in the Spring after frost but remember that birds do nest in them. The other problem then is that it might encourage more, quick new growth which might leave you feeling it needed another trim later on.
4 Jul, 2011