This garden exemplifies a good use of the two main groups of plants that can be used to cover and decorate walls. Wall shrubs, such as the Pyracantha forming the dramatic garden archway, tend to be slower growing than the other group — the climbers. Climbers can be divided into free climbers, such as ivy, that use aerial roots to self-attach, and clingy climbers, such as clematis, which need some sort of exterior support (like a trellis) to cling to with their tendrils or leaves.