A keyhole garden is a type of compost garden that originated in Africa. Biodegradable scraps go in the middle, and the plants all around are fertilized. I have converted the basic concept of the design into a landscaping asset for architectural rendering with a PBR setup in Cycles.
To use this model, append it as the **GROUP** (NOT individual objects) 'Keyhole Garden' into your scene. All objects are parented to the 'Keyhole Garden Bricks' object for easy positioning. The model has physically-based shader setups, complete UV maps, and is ready to be rendered upon purchase (unless custom work is desired).