Colours can be used as garden features in their own right – edging a path with the blue and grey of catmint (Nepeta) or a rose border with the yellow-green of Alchemilla moths (lady’s mantle) are good examples.
The overall shape and form of every plant must be taken into account. for they will largely determine the final effect of the planting, particularly the way it appears in winter. Height and spread can be used to advantage when you want to provide sentinel effects in borders or to highlight a gateway or path.
The ultimate size and shape of all mature plants can be predicted with sonic. accuracy. These dimensions may be reached within one or two years, as with perennials such as Acanthus spinosus (bear’s breeches), or it may be many years or even generations before a plant reach- * es its maximum height and spread. The beautiful blue cedar, Cedrus libani ssp. atlantica ‘Clauca Pendula’, for example, will take generations to achieve its full height and spread, but it will need the space in which it can grow and develop.