These are native to Mexico if I remember correctly. The clematis and pink Chinese jasmine (Jasminum polyanthum) were growing a bit slowly, so to get something blooming on the arch, I decided to try cypress vines this year. I don't know if I'll do that again - these things are insatiable! They're really pretty and I like the feathery foliage, but like many other relatives of the morning glory, they're very aggressive. It's impossible to keep up with the thing to deadhead it, so I'll probably be pulling up seedlings all next year.