A vertical planting system is formed from at least two individual containers 4, 5 which have interlocking members 14, 15 which allow the containers to be releasably connected together. The interlocking members also enable a first container 4 to be held at a predetermined angle of rotation to a second container 5. The planting system may be a hanging planting system. The interlocking members may hold the first and second containers at an angle of between 150-60°, preferably 137.5° ± 1°. The planting system may have irrigation means wherein a main irrigation conduit 11 passes through each container with there being a branch conduit that allows fluid to flow into individual containers. The planting system may also include a support framework for attaching the planting system to a wall. Also disclosed is a method of forming a vertical garden or green wall using a plurality of afore described containers.