The barrels are made of French oak, stained with a red wine that smells delightful! They are hardy and beautiful. They also act as a visual and acoustic softener for the otherwise hard space.
After designing the spatial orientation using Google Sketchup 7, we placed the barrels in position and filled the bottom with drainage stone (13mm gravel). We added 30% compost and the rest potting soil mixed with a bonemeal to boost root growth. Note: barrels were drilled in the base to allow for drainage.
The barrels are planted according to companion planting methodology - placing plants and herbs together that are mutually beneficial, e.g. apple trees and alliums (onions family).