When it comes to bloom colour, there is a multitude of colour schemes to put into play in a garden setting. The choice is definitely a personal one. However, there are some basics of colour theory that can be used effectively in garden design.
Monochromatic colour schemes limit themselves to the use of only one colour. However, the colour can appear in different values, i.e., lighter and darker shades. A monochromatic colour scheme can give a unified feel to a bed. To create more interest, choose plants with a variety of flower shapes and sizes.
Analogous colour schemes extend the colour selection to include colours found next to each other on the colour wheel. For example, you could mix red, red-violet, and violet, or orange, orange-yellow, and yellow. This scheme gives a bit more variety but still has a harmonious feel to it.
Complementary colour schemes combine colours at opposite ends of the colour wheel, such as pairing orange and blue, green and red, or purple and yellow. The effect can be quite dramatic, especially if you use very bright colours (e.g., a bright red flower against some bright green foliage). However, such combinations can also be tiring for the eyes if overdone. For a softer effect, use complementary colours in paler tones.
Pastel colour schemes involve soft colours such as pink, lilac, or peach. These colours give a peaceful, soft feel to a garden, but can sometimes appear washed out in bright sunshine.
Warm colour schemes use colours that suggest warmth, such as red, yellow, and orange. These colours often make an object appear closer. Warm colours are thought to evoke warmth and energy. Red is the most powerful colour.
Cool colours are those that suggest coolness, such as blue, purple, and green. These colours make an object seem farther away and are sometimes used at the end of a small garden to make it appear larger. Cool colours are felt to be calming and restful.
White flowers can add some much-needed brightness to shady areas of the garden. However, bright white flowers can sometimes draw the eye and throw off an otherwise nice balance of colours. Some people use white blooms to separate other colours that may not appear overly harmonious together.
Colour schemes can be applied to an entire garden, a specific bed, or one part of a larger bed. The best way to decide on a colour scheme or schemes is to visit existing gardens and see what colour combinations appeal to you. Look through magazines as well. Try cutting out some plant images from magazines and playing with different combinations to see which ones look good together.