In the same way that rhythm and repetition in a garden is relaxing on the eye, simplicity too brings its sense of calm and restfulness to a garden.
A garden with a little of everything in it tends to create a chaotic muddle. If there are too many things going on, your eyes struggle to take it in and the garden becomes restless and uneasy on the eye.
Simplicity in design follows the, less is more, motto of architect Mies van der Rohe, an early advocate of simplicity in design through his influence on the Bauhaus movement and championing of the Modernist movement, which allows form to follow function, to create open spaces and a simplicity of design.
The red border at Hidcote Manor (pictured right)

Look at nature
In summer cycle along a winding country lane lined with pretty cow parsley stretching into the distance.
Walk through a wood in spring and experience the magical sight of a carpet of bluebells, in the same way plant in drifts in your garden to create a dramatic, simple, impact.

How to achieve simplicity
Limit the number of different materials used in your garden and try to link them to the surrounding materials or those used in your house.
For example: match the materials in the garden to either the colour or type of floor materials within the house. If you have wooden floors this may be done by matching the floor to a decking timber or, if you have floor tiles, try to match these to a similar type of paving. If you have walls or steps in the garden to build, use the same bricks that you have in your house.
Limit the number of features within the garden or in one area. Do not clutter up space.
For example, in my garden the pots on my patio seem to multiply like magic, due to impulse buys, presents or other’s cast offs, every so often we have to have a cull of the more cracked and tired looking ones to reclaim back some of the space.
Eclectic can easily become confused and messy.