I have a P. Incarnata I started in a 14" pot with a 4' wire obelisk trellis. It's almost to the top. It's on the deck but I plan to bring this one in winter. I guess they can get 15-20' long so I have to figure out how to limit this one. Options:

Trim/prune, will it just then "fork" at the trim point? That wouldn't limit it for very long. Will it put more shoots up from the ground?

Try to train it back down the trellis? Will it only just grow up?

Let it grow over the deck and then trim it back in winter to detach it from deck and bring in.

One think I'm hoping is that it puts up more shoots to cover more of the trellis. Do they do that the first year or do you have to wait for it to "spread"?