I grow Corkscrew vine every year,I just love it's fragrance.Mine grows up the front of a 15ft South facing deck,mostly full sun.Unfortunately I have never been able to harvest seeds from the vine because my season is too short,the seeds are rather expensive, but they are worth it.
I also have a 12 year old fussy Wisteria.I have had a few sporadic blooms on it in the Spring,but the buds usually get frozen before they get a chance to flower.
I know from experience that improper pruning is the most common cause of non flowering Wisteria.There are many sites that will provide information on the correct proceedure of doing this,I'm sorry I can't link you to any at this time I have not saved the info.
Good Luck with your vines, enjoy!

The previous post from thistle is correct - pruning, pruning, pruning! Let me guess: the one trained into a tree gets pruned regularly to maintain the tree shape, and the one on the fence just grows wild? There's your answer right there. You have got to stay on top of these things or else they just spread leafy vines everywhere.

You have to know a couple of things about how they grow to get it right. Google "pruning wisteria" for more info. To quickly summarize... The flower buds are set at the end of the summer, then grow out and bloom in the spring. The green leafy runners that the vine sends out do not produce any flowers. If you pinch them off the new ones after they have six or eight nodes (sets of leaves), they will develop side shoots that may flower later in the spring or the next year.

I have a 25x10 foot wistera here in Chicago that blossoms consistently. I am training it to grow and cover a two-story brick wall, so I am pruning and rearranging it all the time to grow where I want it. I also have another in the same spot. It has never bloomed (it started as just a six-inch sprout two years ago!) but then I have also never pruned it.

On 90+ degree days, these things are rampant. I have seen either of them extend a shoot by a foot from one day to the next! When it's cooler, in the 70s, they will barely grow at all.

thistle .. I too live in Southern Ontario and LOVE my corkscrew vine .. I dont think I can live without one =) You can over winter it in your home. The rootball developes tubers . If you give your vine a good cut down and over winter it indoors and give it a head start for the summer season.

I have both Corkscrew and Snail vines. They are about 3 years old and I winter them over inside under HID lights. This is the first year that the Corkscrew vine has bloomed and it's just beautiful with a wonderful scent. During the growing season I have them in full morning sun and almost full afternoon sun. They are in 24" pots and get BIG. I cut them back to a couple feet, enough to get them inside. I cut back on the amount of water and I don't feed them while inside. The Snail vine continues to bloom throughout the winter. I'll find out soon enough if the Corkscrew vine blooms over the winter also. I like my Snail vine but I love my Corkscrew vine.
Karyn

So, what everyone is saying that I have read, they do not produce seeds often? (corkscrew vine) This is my first year of growing them, and I have them planted all over my yard. I live in zone 5. (cold) I was wanting to get seeds from them. This has been a very wet spring so far, rain almost every day for the past 3 weeks. They are growing, about 4" tall so far. all in the sun, (When we get it) But it is almost July now!! And they are all only 4" tall. Do you think mine will flower at all this year? We usually always have tons of bumble bees, since my yard is full of other flowers. So they can pollinate them right? So I will get seeds? How far back do you cut them to bring them in, in the winter? Mine are planted directly in the ground, on fences, trellis, and around my deck with lattice.

Because of the Flower shape a Bee cannot get in to pollinate,I believe they are pollinated by Ants.I am trying again this Year to get some Seeds,Fingers crossed I will be successful .

Thank you thistle. This is my first year trying to grow them. Have heard so many different things about them, I think I am confused!!!