I have two 'Group 2' clematis (Nelly Moser & The President) which regularly get taller that their 9' support system. They currently have a bunch of stems waving around in the air 6"-18' above the top of the trellis. Typically they eventually fall down from their own weight and make a tangled unsightly mess of branches and flowers halfway down the trellis and confuse my fall pruning efforts. Can I prune or pinch the upper vine tips at this time of year to shorten them a bit and encourage branching and flowers lower down? Would it be better to leave the stems uncut and try to train them to turn around and grow back down the trellis? The plants were given a light pruning this spring and shortened to about 4' or 5' . I also bought three new 'Group 2' varieties this spring. Is there something I can do to prevent them from getting so tall?
No, you would not want to cut the tops of these back at this time of the year. What you really need to do is choose kinds that are the right sizes for the available spaces.
The clematis I am growing are described as growing to 6'-10' (Nelly Moser) and 8'-11' (The President) which seems like a suitable size for my 9' tall clematis frame. The new varieties I bought claim to be 2.5 to 3M max. height. I presume mine are on the tall side due to the site being partially shaded. Is there something I can do early in the season to try to keep them from growing too tall?
