Question about trumpet vine training

I just accidentally purchased two trumpet vines from a nursery that is selling all it's stock at 1/2 price because they close for August. The reason I say accidentally is because I certainly don't need any trumpet vine, I have too much of it growing in the yard. When I saw them at the store I thought they were wisteria, because I really want some for the yard and these vines are being trained into a tree form which is what I want to do with some wisteria. I know that the two don't really look that much alike but once the idea was set in my mind that they were wisteria there was no changing it. So, I found a couple that had a price sticker, and not bothering to look at the name of the plant that was in smaller print, I bought them - all sales final. It wasn't until I got them home and carried them into the back yard that I realized my mistake. Finally I get to the question, how successfully can these be trained to grow upright. They are supported with sticks about 5 ft tall. I want them to be a foot or so taller. The nursery has allowed vines to sprout from the lower parts of the "trunk". Should they be cut off to encourage more growth at the top? I think with wisteria you can ultimately remove the support because it older growth is strong enough on it's own. Is that possible to do with trumpet vine or will it always need to be supported with poles to maintain the tree form? Thanks, Dave

Decided against the above. I bought a metal arch for them to climb to their hearts content. It will serve as an entryway to one of the paths I am putting in the garden. Cave