When we finished 'decorating' the house the creativity had no place to go but to the back yard. We still have a long way to got, but we did get the bottle tree constructed. I would like to have blue bottles, but they can be hard to get your hands on (unless you want to buy them). Anyway, our tree has it's own special charm.
Folklore says that evil spirits slip into the bottles and can't get out, protecting your home.