A number of plants have a striking architectural or sculptural impact; some from their foliage, stems or flowers, others from their natural growth habit. There is a great variety of forms and effects, ranging from the arching, thistle-like leaves and stately, upright flower spikes of bear's breeches (Acanthus spinosus) to the low, spreading mass of a prostrate juniper (Juniperus communis 'Prostrate').

Structural plants are often used singly as a focal point, but they are also effective as part of the design framework. Placing a pair of structural plants, one on either side of a path or doorway, acts as an enhancing frame, while a single plant at the end of a border provides a visual fullstop.

Architectural plants are excellent for visually linking the house (or other hard feature) with the garden - the sculptural, but living forms bridge the transition from hard materials to soft planting. Including a few strongly shaped plants in an otherwise informal and unstructured scheme contrasts well with the soft lines of the free planting and helps to give the design a focus.

With herbaceous or deciduous plants, plan the scheme so that other features or plants provide a similar function during winter months. For example, a clump of dwarf Gunnera (Gunnera magellanica) could be planted next to a group of red-barked dogwoods (Cornus alba) so that the dogwoods become a spectacular feature once the Gurnera dies back.