United Kingdom 
I have a leylandii hedge about seven feet tall and about
twenty years old. Over the past three years it has died and I find that on my neighbours side of the hedge it is completely covered in ivy, so much so that the hedge cannot be seen. Could this ivy be the cause of the hedge
dyeing?
6 Jul, 2012
Answers
hi patrick i dont think it will do your hedge any good its like when you put a conifer in a pot and place it right against a wall eventually the side against the wall will brown and die off lack of air rain and light
6 Jul, 2012
There are better conifers than leylandii for hedging, and lots of evergreen choice so if you possibly can have them out, improve the soil and have a new hedge, I,m sure if you go to H and hedges at the bottom of the page you'll get lots of ideas
6 Jul, 2012
The ivy will certainly have caused the branches on the neighbour's side to die but I'm surprised it affected your side as well. In any case its academic as if the whole hedge has died it will have to come out. Maybe you could liaise with the neighbour about killing the ivy before you replant with something else?
6 Jul, 2012
I have some of the darn stuff surrounding my garden. (Grrr!)
If I had my way I would replace it with either Beech or Hornbeam..
Maybe, one day.
7 Jul, 2012
Just a thought,generally Leylandii are hated,if at all
poss. I might suggest that you replace it. It had crossed my mind also that perhaps your neighbour let the ivy grow to try and kill the Leylandii,like Pamg says, there are some much better plants for hedging
7 Jul, 2012
Doubt it. Do some soil tests. Or maybe just get rid of the horrible things.
6 Jul, 2012