This not one I thinking about but does show arch it to high in center for muscadine vine by about foot to pointed at top in link. What looking for easy walk under so top more rounded.you want reach throw wire about up to wrist for picking. I use this design because lower squares are good place kids pick just walking kids they work twins in family be 1 year old Thursday 18th party 20th not my kids Clara Jane and Lilly Ana just now walking, but hold hands up high to walk because of training steps holding hand up lol. There to many ways to do trellis for muscadines for one to fit all. I picked 2 5 gallon bucket full off friends vines on my old knees the best picking was under vines ground was soft and rows was long a small deer was eating at other end long row vines underside. Here is a link that might be useful: Cattle panel This post was edited by gator_rider2 on Mon, Apr 15, 13 at 21:50

Not sure if this is helpful, but I have 2 Valiant vines and I don't do anything to them, just let them ramble up a 3-wire support, then they continue up onto the fence and into the nearby trees. In the spring I prune out dead wood and canes growing where I don't want them to, and shorten things up a bit. They are so vigorous that about twice a year I go after them with hedge shears so I can maintin access to that part of the garden. Maybe you can do the same for your arbor, just pruning with shears when things get unwieldy and you need to shape the vine? Don't cut to the ground, you need some of that old wood to provide the new fruiting growth. A photo showing the grape at the back of the garden covering it's support, the 6-ft fence, and then heading up into a nearby apple tree:

A neighbor of mine had a trumpet vine growing over her stockade fence that never flowered in all the years she had it. Last summer she said she was digging it out and getting rid of it because it never flowered. She never "got around" to it and this summer it is blooming fabulouly! Maybe it overheard us talking about it's proposed demise. LOL. :) :) :) :) She didn't do anything different to get it to bloom. Maybe it just takes years before it blooms? Maybe it is because this summer has been incredibly HOT? I tried planting trumpet vine this year and it never even grew.

Clematis and Morning Glory are delicate and polite, you can plant them anywhere. Morning glory will spread its seeds and come up in unexpected places in future years though. I'd research the size of the clematis on a clematis site, mine haven't every really been "fillers" of space, but they're pretty. I have to agree with karynl on the trumpet... in a sense...they're invasive, sturdy, and impossible to eradicate...but they're gorgeous. My recommendation is on a fenceline or place where you mow and you can mow around it to keep it in control. I've seen them covering and topping 30 foot trees in pastures.