What about a climbing rose? I have a bad case of "fence envy" and wish I had one so I could cover it with roses. The only thing I would wonder about is how wet the area is...roses need moisture but also need good drainage.

There are plenty of varieties that are low maintenance...my best advice would be either visit the Rose Forum or the Antique Rose Forum and see what they recommend. Or contact Ashdown Roses (I'll post a link below) and see what they think. They are good people there and are always willing to help.

Two climbers that I grow on an arbor in my yard are Field of the Woods and Noella Nabonnand. Both are pretty much disease free and bloom beatifully. And both are very fragrant.

Carole

Here is a link that might be useful: http://www.ashdownroses.com/

Another possibility is the evergreen clematis, C. armandii, if it would be hardy for you. It is VERY vigorous, so could cover a lot of the fence with just one plant. It flowers in spring. Planting other clematis (not evergreen) along the row would give you more flowers, and the C. armandii would give leaf coverage when the others died back. Roses could be mixed in as well, since they and clematis are usually a good fit. My only worry would be that the C. armandii would be SO vigorous as to overpower anything planted with it. Since I haven't grown it, I can't speak from experience.

While the Japanese honeysuckle is pretty much evergreen, it is SO invasive that I heartily DIS-recommend it!

Carolina Jessamine (Gelsemium sempervirens)is also semi-evergreen, also rampant, and flowers yellow in late winter/early spring, and is hardy.

Confderate Jasmine (Trachelospermum jasminoides) may need training to go along the fence, but is another vigorous grower in the right place. Hardiness, again, might be a problem.

Five-leaf akebia has more inconspicuous flowers, but is hardy.

And, depending on the microclimate, some of the true jasmines might be hardy for you.

Is it just the split rails or do you have wire fencing on the inside? We do and I found that it was lots easier for vines to catch hold and follow the fence instead of going through and onto the ground beyond the fence line. Akebia likes to grow tall and will catch hold of any shrubs or trees on the other side. Kiwi is a nice fence cover but it is deciduous. I'd go more for an old fashioned rambler rose than a climber. The climbers want more than 4' high support or they either flop or grow huge and unsupported.
Bignonia (sp) is also a great fence cover but it needs support, something to cling to. Perhaps you can tack aluminum box fencing (I know I have the wrong term), not chicken wire) from the top to bottom rails in the sections you want vines to grow. You can always add on as the vines grow.

How about Goldflame honeysuckle "heckrottii" or Alabama Crimson honeysuckle? They are not invasive and are really pretty - may keep some leaves for you and could be planted with clematis and Carolina Jessamine.

I recently saw some beautiful photos of Evergreen Wisteria (Millettia reticulata). This is not invasive like regular wisteria and doesn't get so heavy so it won't tear down your fence.