I too planted a trumpet vine and was sorry. I've been Rounduping it for last 3 years and still haven't killed it all. As to if it would survive in dappled shade, my comment would be...would you care?

Yes, I think purple hyacinth bean would be a good substitute (I'm assuming your fence has full sun)...as long as you don't mind cleaning it up when the first freeze gets it. Be sure you get the pods off when they are ripe or you may find you have many more volunteers than you want. I find that you have to start them from seed inside and let them get a couple of sets of leaves before you set them out. Being beans they need a 24 hour soak in water before planting. Keep them watered well when they are young...when established they take off about 15 feet across or so. They are a twining vine...need something to climb..like a thin trellis, wires, or chain link fence (where I grow mine). The flowers are fragrant and do attract bees, if that's a problem for you.

Thanks! How soon prior to planting would you start them indoors? Also, how many seedings should I put across one section of the chain link (standard 4 foot length I think)