I'm having the same problem with my arbor. The morning glories have been less than impressive and at this rate, they might look good and bloom a week before frost. Instead, I've decided to put in clematis vines. They're sitting on the porch right now, until it cools off enough to go dig :)

I'm putting two purple and two white, to replace the morning glories and moonflowers I tried earlier...the moonflowers didn't even sprout. Disappointing, but gardening is all about learning what will do well in your area.

Canary vine is pretty too (and non-toxic) but also takes a long time to get started, at least in zone 4. Sorry I don't have better ideas for an annual vine, but would clematis or honeysuckle work in the space? Maybe luffa on one side of the arbor, with perennials on the other?

Starting vines can be tough, I know I had to toss my morning glories this summer.

Might I suggest a perennial vine that I've had great luck
with - mandarin honeysuckle? It is a less common honeysuckle variety, with a vine that eventually becomes woody and gorgeous flowers (that are unscented). Mine has been running along my garden fence for several years now and it has grown and bloomed beautifully every year. It wasn't that hard to get it established either. And each year all I have to do is train the new growth in the right direction.

Otherwise I'm afraid I don't have any experience with annual vines except morning glories. Whatever you decide to try, good luck!

I have a clematis Rooguchi on a rose trellis that would be perfect for an arbor. It's not overly large, it blooms all season long, and best of all, you just cut it to the ground each winter. It is always blooming before the roses.
No thorns either.

Good question! I have tried unsuccessfully to grow clematis on a trellis for a few years in a row. I remember my dad had beautiful purple clematis growing up twine trellis on each side of our side porch, so thought I could grow some, too. Evidentally not. I might try the Rooguchi clematis if I can find it.

I have not gone to roses, although they look lovely. I would like a perennial for my trellis. Any ideas? I would love to have something that blooms most of the summer and has fragrance..or two different ones...one for blooms, one for fragrance. All ideas are welcome.

as for the moonflower, start by seed early and transplant or buy from a greenhouse already started. It grows much better this way for me.

Donna, is your Rooguchi in full sun? I was reading about it on Dave's Garden and almost everyone mentioned growing it in morning sun. I'd love to have something growing with my Sweet Autumn clematis, but that means full sun.

The thing about clematis is that it has a root system like a tree, so it likes to be planted like one - big, big planting hole. Also, it likes its feet to stay cool, so planting, say, some daylillies or other perennials around to shade the bottom can help. One nice thing about them is that they can grow out of shade ... as long as they can get good sun on the top of the vine.

I have, and love, the climbing hydrangea. But it only flowers in the spring. It's a slow starter, but after a year or so, it really takes off. I have it climbing up an oak and a sugar maple. Pretty red bark in the winter adds interest to the tree trunks.

I have probably not been giving my clematis' roots enough room, so will try one more time and add shade plants near the base. My trellis is out in the full sun.

I planted sweet peas years ago by our fence that has lattice on top..strung some twine back and forth, and they love it. Some people say they're annuals here, but mine always come back in full force. And they're on the north side of the house. They may work for you, too. Not expensive, lots of color all summer and good fragrance.

Thanks for all the suggestions. I have some clematis in my yard that's is not in a good spot. Does anyone know if they like to be transplanted? My arbor does get sun all day but I could shade the base with other marigolds or zinnias if need be. I also have autumn clematis that is growing up one of my evergreens in the front (an uninvited surprise). It would be nice to have a late bloomer like that on the arbor too.

They don't like to be transplanted. But that doesn't mean they can't. I've done it. Just pretend you're transplanting a tree.

Passionflower depending on the variety and zone can be either a annual or perennial.