We've built a fairly sturdy pergola and I'm considering growing a wisteria on it. We've since paved the area with nice cobblestones and I don't want to put the plant into the ground in view of potential problems caused by aggressive growth. Instead, I'm thinking of planting into a large container.
Wisteria are used for bonsai all the time, but even in a big patio container, you'd have to consider how you'd deal with the roots - if they don't crack the container within a few yrs, the plant would die if roots are not pruned hard, and that's a major (heavy) job when you deal with something that size.
I have a wisteria in a pot that is 15"x15". It started out as a stick and grew well over the next few years. I'm in an apartment and it grew up the support I had to the balcony above me and wrapped around their railing. However my neighbours are not plant lovers so they didn't do anything with it. Walking around the westend of Vancouver I noticed a couple of other wisteria plants on balconies and they do very well. So far I haven't had a problem with roots breaking out of the pot.
I've got three wisteria in pots on a 40 ft x 7.5 ft trellis (has two wires) on one side of my house. I only planted them this year and they are in fairly large pots. The two I have had the longest have each grown about 20 ft this year, the third I just got and so has obviously not grown much. Rima makes a good point and I will likely need to get some larger containers at some point.
Or cut back the older woody roots by 1/3 when repotting... but always avoid the new feeder roots high up near the trunk, and if the mass of those are only on the older longer roots, you'll have to do them in stages (over a few seasons) til more have developed higher up.
I have been growing Wisterias for the past 20 years, and the urban legend about the aggressiveness of their growth in colder temperate areas is a bit exagerated. There is no doubt that it can spell trouble in warmer areas, but not where I garden - which is on the warmer end of USDA zone 7. I have one in a container for 10 years and there is no sign that the pot is in danger of busting. (The 17 gallon container with the black bamboo in it, on the other hand, lasted just 3 years!)
It's not like their growth can't be controlled. But you do need to know that it's all in the taming of the plant. I.e., regular pruning. If you can commit yourself to prune and train it consistently, it should not cause a problem with the roots. But if you can't promise yourself that, then, it's not the right plant for you. Because it's the untamed wild thing that gets out of control.
If you are really concerned about out of control growth, there are other varieties that are tamer. The North American wisteria, Wisteria frutescens, is a good example.
You will need a fairly large container to grow any vine to support sufficient growth to cover that large pergola.
Thanks for all the info, everyone. I debated with myself back and forth on this, and shopped at nurseries (where I couldn't seem to find the right plant). Anyway, I chickened out and bought a clematis armandii 'Snowdrift' instead, which I've had great success with in the past.
Although I guess if I do find a choice wisteria cultivar, I can see myself taking down that clematis...
If you are interested, there is a rather large specimen of Wisteria, growing wild, in that triangular strip of greenery, bounded by East Columbia street to the north, Front Street to the south and Patullo Street to the west (not really reaching Patullos bridge, but from the junction of E Columbia and Front to the railway bridge). You should be able to see it if you drive along Front Street as you approach Columbia. When I passed by a week ago, the vines have reached Front Street. Drive by in June and look for the flowers up in the trees.
When we first moved to BC, in the late 1980's, I had noticed that this particular wisteria extended it's vines to the junction of Front and E Columbia Street. But in the early 1990's, intense heat, fueled by cresote, of a nearby CN railway trestle fire destroyed all of the vegetation in that corner of the green green triangle.
I've heard mention of this particular vine, but although I live in New West, I haven't noticed it before as it's not on my usual route. I'll try to keep an eye out for it.
There's a house in my neighbourhood that has a wonderful garden (I believe the house is also a private gallery) and they have a nicely trained wisteria growing on a small trellis. It seems very well-behaved, which led me to think I could try one of my one. But after reading all these horror stories about wisterias wreaking havoc, I've chickened out. Who knows, after I get used to the new pergola, maybe I won't be so protective. I've grown a wisteria in a container before, and because I neglected it, it didn't get very aggressive (and still flowered).
You don't have be scared of the wisteria if you know how to prune it. It's like the circus lion tamer who is not scared of the lions under his charge. But you have to be sure that you can be the tamer, not the "tamee". With correct pruning and training, the wisteria is the most rewarding woody vine there is.
Hmm...you've given me food for thought. It's not so much the pruning - I'm ok with that We've just built this pergola (a bit of a horror story but that's another matter) and I'm loath to grow something on it that might cause problems later on. A main concern is the vines themselves as they wrap around the main post. I've seen pics of how thick the vines can get. (Probably silly of me as who knows how long it took for them to get that big). I have a couple of very strong large containers, but if I have to root prune, how do I get at the roots? Not as simple as it would be if the plant was in the ground, I would think.
I don't root prune the two wisterias that I have in containers. The containers themselves seem to restrict growth enough. I do root prune the "standard" or tree trained specimen in the picture above, but only once every two years, to maintain good flower production. This is because it is grown in an area which is well fertilised (adjacent rose beds). In our case, the need for root pruning is heralded by the increased profusion of young tentacle like shoots.