The genus Ipomeoa, especially Morning Glories are probably what you want. Also Cardinal Flower, and Moon Flower, but if you want something that will grow at least 15 feet you should look at Scarlet runner bean.

Steve

Here is a link that might be useful: Iowa State article on Annual Vines

Dicentra scandens might work. (I'm ordering one.) Yellow bleeding heart vine. It would probably be an annual in Zone 5; I'm hoping it will be perennial in my Zone 6 garden, and if you live in coastal Mass., Zone 7, it should definitely be perennial --and you won't want it. Don't know what Zone you're in.

It's supposed to grow and flower quickly so it can be enjoyed as an annual in the colder zones.

I've grown scarlet runner beans where they received either only morning or only afternoon sun. The hummingbirds love them and if they find yours will scold you if you move while they are at the flowers. If you hear the buzz of their wings soon enough to stay still, it's lovely to watch them visiting the blossoms. If you grow morning glories, you'll need to keep a sharp eye out for volunteers next spring as in some areas seeding is an issue.

Just checking that you know that most pergola structures need something added like wire fencing or wire strands to allow vines to grow up them since perola uprights tend to be much too large in diameter. Beans and morning glories grow by twining the stem, so they will wrap around something a bit larger than the clematis which wraps the leaf petioles around the supports and so needs relatively fine supports.

Also, I don't know if you have good sources for clematis near you, but if not,
Brushwood Nursery in GA http://www.gardenvines.com/
Hummngbird Farm in ME http://hummingbirdfarm.net/clematis.htm and Silver Star Vinery in WA http://www.silverstarvinery.com/default.asp
are all excellent sources of clematis in a wider variety than I can get here in my neck of the woods. I have ordered from them all and been quite happy with the plants. Silver Star has the largest plants of the three places, but all are large enough to plant out in the garden without needing to fuss over them. All 3 have plant lists for the season up, but Hummingbird Farm isn't taking orders yet. Make sure you check out approximate vine heights as you shop since clematis come in many different heights. Clematis on the Web is a good resource to look up varieties for more information and photos. There is a search function using part of the name or you can use the alphabetical list.

Do you have a photo of the pergola you can post?

Here is a link that might be useful: Clematis on the Web

Thanks,

I've ordered scarlet runner seeds and some morning glory seeds. I plan to start them indoors in some peat trays. I'm also going to order some clematis. Looks like the Montana variety gives the best growing height. I'll use some of the links provided for the growers, thanks for the links!

I'll try and grab a photo of the pergola to show here. The three base legs of the pergola are about 6" diameter, so i think i'll use some wire to encourage the MGs and SRs to start running up.

The links that Babs gave you for vines are all excellent sources. If you are looking at Clematis montana, let me suggest montana Mayleen. I'm growing that on my pergola. It's beautiful, fragrant and will grow from 20-30 feet. I wouldn't, however, try to grow it in a pot.

Steve

I'd echo caution on Morning Glories. I'm in zone 5b-6 and found the seedlings to be a PIA. I am still picking out seedlings from plants that lived 10 years ago. Also, they don't really get big and cover a fence until late in the season (like a lot of annuals)
Save your money and get bigger plants of something else.
idabean

MAGard79 -

You don't have your zone listed, but be sure to check before you order a C. montana. They aren't as hardy as some of the Clematis. I'd love to grow them, but I'm pretty sure that they wouldn't bloom for me since they would be killed to the ground most years. That might defeat the purpose for you since you want flowers and height. The zones are average coldest temperature over the last 50(?) years. If you keep an eye on the temperatures at your home, you could use this instead of your official zone.

Try using large square netting that you can buy at any Agway store and it much easier to tack that into your pegola posts. The vines appreciate the netting squares to grow up and around and is much more athestic than wire, as it disappears when nothing is growing on it.