Having to plant in shady areas is often frustrating for gardeners. They feel as though they are very limited in what will grow well and believe that colorful flowers are an impossibility. Once you understand the different categories of shade, you will see that there are a great variety of plants that will do well in the shade.
Category 1: Filtered or dappled or open shade. It is the brightest shade that is produced by openly branched trees such as honey locust or birch. Tiny patches of sunlight flicker across the ground, but the plants are not exposed to direct sunlight for any extended period of time. Lathe work over a patio can provide this type of shade.
Category 2: This light shade is characterized by little or no direct sunlight, but there is bright light. Any sunlight would be in the early morning or late afternoon. North sides of buildings, walls or fences produce this type of shade as well as a single tall tree with a heavy canopy of leaves that cast a complete midday shadow.
Category 3: This is medium shade that can be described as an open area that has no direct sunlight due to clustered tall trees with a canopy of leaves high off the ground. Often these trees have been "limbed back", that is, pruned to allow the entrance of bright, but not direct light.
Category 4: This is heavy shade. It includes areas where light is obscured by a thick stand of trees in which the branches hang closely to the ground and under stairways and decks. Shade under unpruned evergreens would also represent this type of shade.
To improve light conditions, it is useful to have trees "limbed back" to allow the entrance of more light. It will increase the vigor, bloom and number of plants that will do well in a shady environment.
Remember that no plant grows quickly in the shade. Gardeners often make the mistake of planting sun-loving plants in the shade in the hopes that they will grow faster than shade-loving plants. These sun-loving plants will also grow slowly, and in the end will most probably die due to lack of light. To be successful with shade gardening, plant types of plants that are suited to the category of shade you have.