To fully realize the potential of the shade in your garden, you must first understand the type of shade, the type of soil, and the amount of moisture present in your shady areas.
Full shade describes the lighting on the north or northeast side of buildings, walls or fences where, during the growing season, the ground remains in shade through the entire day.
Medium or part shade is the shade cast by evergreens or dense, deciduous trees such as maples or lindens. Area under decks or stairwells, or in south-facing but deeply recessed entries may also be classified as medium shade.
Light shade prevails in a north-facing yard under the canopies of ornamental or more open deciduous trees, and in the areas of the garden which usually receive only morning sun.
Soil in shady areas is often poor because of the proximity of structures, or trees whose roots have depleted natural nutrients. This is important because shade plants typically do best in soil enriched with organic matter. Compost or sphagnum peat moss help the soil hold moisture, reducing the need to water. Amending the soil heavily with four inch deep compost or sphagnum peat moss restores nutrients.
Most shade in Colorado gardens is dry shade, meaning that without watering, the soil is generally dry. However, if a shaded area receives runoff from rain or sprinklers, it may qualify as moist shade. Determining if your shaded areas are moist or dry will help in selecting appropriate shade plants.
For “Shade gardens: soil preparation” refer to message number 1054.
For more information, see the following Colorado State University Extension fact sheet(s).