About the Bottle Tree
I found I great website with articles and photos of Southern things of interest. Stones in My Pathway - photography by Bill Steber.
Here is what he had to say about Bottle Trees:
Once a common site in the Southern landscape, the bottle tree is now an increasing rarity as ancient folk beliefs and customs fall from common usage. The origins of the tree go back to the 9th century Congo where hand-blown glass was hung on huts and trees as a talisman against evil. The practice consists of removing the foliage from a tree (preferably a cedar because all the branches point heavenward) and placing the tree in the yard of the house. The bare branches are then covered with colorful glass bottles that attract any evil spirit that may be lurking near the house. The spirit becomes mesmerized by the play of sunlight through the colorful glass and becomes trapped inside the bottle. When the wind blows past them, the moans of ensnared spirits can be heard whistling on the breeze.