Living structures can be very interesting and I've seen some really good examples in gardens that are open to the public. They are mostly made from willow which can be woven into many shapes or to form a living boundary fence. The reason they are called living is because some of the stems used to create the structure root in the soil and grow to form new shoots. This does mean that annual trimming is needed to maintain the shape, but at the same time it adds interest to the garden. Creating a living structure is very simple to do and all you need is a few pruning tools and a bundle of willow sticks in various thicknesses. In my garden I'm making a small living arbour that will create a sheltered area where I can sit and admire the garden. If done now the willow sticks will root and the new growth woven in to the existing framework.