Wisteria can grow and bloom nicely without pruning, but because they grow rampantly, regular pruning helps keep them more manageable. Oriental species of wisteria bloom on old wood, so to get blooms next year do your major pruning right after the vines finish blooming in early summer. You can trim long shoots back to 6 inches or so from the main trunk or side branches. In late winter you can also prune out excessively long shoots or trim them back to 3-5 buds per stem. Remember, though, that this will remove some of the blooms for the coming season. Native American species and varieties of wisteria bloom on new wood (many are rebloomers), so timing of pruning is less critical for them.
Wisterias can be propagated by layering. Use a long shoot from the current season's growth. Bend it down to the soil. Nick the stem with a pocket knife (remove a small section of bark), and bury the wounded stem section, leaving the growing tip above ground. After several months to a year, new roots will form. At that time, remove the rooted stem from the mother plant and transplant it to a new location. It usually takes several years to develop into blooming size. But this method is faster than starting from seed, which can take 10-15 years or more to develop blooming plants.