You're a good painter. The barrel's still ugly.
Haha, Yes, covering the hideous blue with lively plants is the trick. You're hilarious.
Rain barrel manufacturers make industrial-looking products, but they can at least have natural pigments.
Perhaps painting it with a natural mud slip and then sealing it could lift its face.
A rain vessel built with long lasting material like stone, clay, metal, wood is a serious commitment.
Like modern people continuing to visit ancient sites, it will attract the desire of people to maintain it, indefinitely.