Hi Izzy, 2 things strike me about this firstly is it getting enough light/sun up top? 2ndly This looks short of nutrients to me? I am on heavy clay and certain plants/shrubs seem to struggle to get magnesium. This year 2 of my Clematis have been yellowy and I gave mine a table spoon of Epsom salts x 2 this summer and they both are now much better.

Hmmm! Think you maybe right...and I've suspected so for some time. When should I move it? Spring? In the meantime, should I do anything i.e. Epsom salts, Drc? Does it need to be on a south facing fence/wall ideally?

Thanks Drc! Any further thoughts welcome!

Clematis Jackmanii, should be planted in full sun (they do tolerate some shade though) with moist, fertile soil that drains well and remember to mulch the root area to give it shade and cool soil. Usually they are pruned in Feb/March before growth begins, by cutting back the stems to a pair of strong buds 6-8in above the ground. I think to move it this year might finish it off? I think this plant is struggling for light and food so if it were me I think I would give it a good feed and then mulch and cover the area in front of the roots with and up turned pot or a large stone. reduce those thin stem by 2/3rds to give it less to do stress wise and re look at it next Feb/march? These are usually low maintenance Clematis so I think its just a case of sorting it out?