Most people believe the bottle tree began in the 9th century in Africa, but there is evidence that it actually began around A.D. 100. The idea of the bottle tree, however, was brought to America by African slaves.
When bottles are hung from the bottle tree and the wind blows, you can hear whistling. It was thought that the whistling was evil spirits crying out after they were trapped in the bottles. It was believed that the evil spirits became trapped at night, and then when the sun rose in the morning, the first light would kill the trapped spirits. Blue is the preferred color for the bottles because blue was thought to attract spirits and ghosts.
Today, the idea of protection has been replaced with a desire to decorate. Bottle trees are added to gardens to add a unique decoration. Although blue was the preferred color in days gone by, today bottle trees contain bottles of many different colors.