I have a metal tool shed in the yard that's fairly unattractive. Is there a hardy climbing plant that would trellis up the side, over the roof and down the other side? It doesn't necessarily have to flower, but something that stays green (in a tropical climate) throughout most of the year would be ideal. Is that impossible? Is it a bad idea to have something cover the roof since I can't get there easily to clean up debris?
Any vine climbing on the roof of your shed would trap moisture and humidity on the roof's surface, and likely promote additional rust development. In a tropical climate there are many vines such as bougainvillea, cross vine, and coral vine that would sprawl and cover the surface, but you may not be happy with the results if they speed the rusting process.