By Shrubby33
Lanarkshire,
United Kingdom 
You're right, of course, about the tendrils. There's a grapevine in there alongside the roses, and that's where the tendrils are coming from. My only worry is that their clinging to the leylandii might retard the growth of the leylandii.
15 Jun, 2017
Answers
Hi Shrubby
ahhh grapevine tendrils
I would remove anything else growing on your hedge as it may damage the foliage
15 Jun, 2017
The tendrils may cause "flags"--little dead twigs--but the foliage of the grapes and roses will do even more damage, since they will shade out patches of the 'Leylandii', which will take a long time to fill in, if ever.
15 Jun, 2017
Well if its a virginia creeper, hack it back where you need to - it'll take over your trees if you let it. Average height and spread over time 30-40 feet high by around 15 feet wide, more after 20 or so years, if left unpruned. Same applies if its Vitis (grapevine)
15 Jun, 2017