United Kingdom 
I have a strange plant growing up through my rose trees planted on obilisks. I have clematis growing through them but this plant is slightly different and very vigorous,. I now spot very small white flowers in it - NOT clematis! I have not removed it before now thinking it WAS clematis as the leaves resemble it so much but i now think it is a weed as yet unknown to me.Has anyone else encountered this plant?
7 Aug, 2017
Answers
You could have a look at Convolvulus arvensis (field bindweed), it could be a possibility being a weed.
7 Aug, 2017
A photo would really help with the i.d.
7 Aug, 2017
Agree, we need a photograph
7 Aug, 2017
Sorry I can't send a photo. Your reply, Hywel, was very helpful and I've managed to find a picture of the very plant you suggested (Wild Clematis) on the internet. Thank you very much for your help.
7 Aug, 2017
Glad to be of assistance :)
7 Aug, 2017
I'm wondering if it's a wild Clematis, known as Old Man's Beard. It has small white flowers and can get very big ... and that may account for the similar leaves.
Can you post a photo of it ?
7 Aug, 2017