I would wait until after the bloom and then prune them hard, bare root them, root prune, and repot in gritty mix or something with some long term structure. It sounds like your potting medium is spent and compacted. I also don't like plants in containers making themselves permanent, so I would prune back to where it starts wrapping around the post and retrain so it's straight up the post. That's just me though.

THX...That sounds like good advice...my neighbor had said he had a suckling come up in his garden about 4 feet from my brick wall...he said he pulled it out but could not get all the root and it looked like it was growing in my direction...actually 2 plants had come up and the smaller one I just yanked out and stuck in a pot....it took a while but it is growing fast now...it's a third of the sz of the bigger one...but you are right...it most likely is from the root stock which would not be desirable...I just started to read-up on wisterias and had no idea they were grafted as they are...so this is a bit disappointing cuz it has been great having something grow so fast and high in the garden...my dad had a wisteria tree in his yard that I loved and I was looking forward to having one like his....looks like I will have to spend the money to get a good one...just out of curiosity I might let it grow another summer...will let you know what it does...I am quite sure it is wisteria...the smaller one I potted is behaving much more like a vine and looks like pictures I see online...I love volunteer plants...this one is amazing with the growth it has shown...it could be a good experimental project for me...with all the vigor it has I could try to sculpt it and make it grow into an interesting form...

I'm still learning about Wisteria myself, so I can't answer most of your questions with any real certainty. But that said, I think you would be fine to twine the stems, if that's what you want to do. I'm learning about how to train them into a Tree form, as I'm thinking of trying it. Often those stems are twined around each other - sometimes using more than one variety/color to make an even more interesting and lovely show when they flower. They grow together like this, eventually forming a self-supporting "trunk". There are many pictures on Google Images. The vines seem to gain strength from this rather than harm. They seem very vigorous and hardy vines, tough to kill.

From the sounds of it, I think you have the wrong plant...! If it's only recently planted, getting rid of it is likely the smart thing to do. I gather that, for whatever reason, wisterias are not as rampant spreaders in the UK as they are in some parts of North America, but they are vigorous growers everywhere- as you've found out ;-). Is it a Chinese or a Japanese wisteria? I have one of both, and both are grown as 'trees'. We planted the Chinese one 15 years ago and keep it to ~8-9'. We planted the Japanese one in 2007 and are keeping it shorter - ~6'. I ignore the complicated pruning instruction you see everywhere and just whack back into the desired framework all whippy new growth as it arises - can be an almost daily task when it is in active growth! All root suckers and growth from below the graft union (assuming there is one) get ripped off (not cut off - I'm trying to remove bud wood...). The Chinese wisteria virtually stopped producing root suckers after 5-6 years of age, but the Japanese one is still producing lots, so it is the more rampant grower in my experience.