Gardening in the shade? A key reason for planting trees, especially in the subtropics and tropics, is to create shade and provide a welcome refuge from direct sunlight for humans and animal, as well as to cool structures. But there is a down side to shade, with respect to growing other plants beneath the trees. In trees with dense canopies, light intensities at ground level can be very low and represent a challenge to landscaping.
<h2> Illumination Levels </h2>
Plants that grow best in shaded environments are known as sciophytes, the opposite of those thriving in full sunlight which are called heliophytes. With respect to optimal illumination levels, plant habitats are defined as follows. Full sun, refers to an average of 6 full hours of direct sunlight. Partial sun/partial shade, indicates conditions of 3-6 hours of daily sunlight. Light shade is often used to refer to partial sun conditions. Dappled (filtered) sunlight is similar to partial shade with the addition of specs of direct sunlight penetrating through the tree canopy.
Over the course of the day the light specs move eastward across the ground. This level of shade presents understory plants in an especially beautiful setting. Full shade designates 3 hours or less of direct sun, typically at a low angle, either morning or afternoon. Deep shade defines conditions where direct sunlight seldom if ever reaches the ground. In nature, for example, this occurs in dense coniferous forests. These designations vary with latitude because solar intensity increases steadily from the poles to the equator. Another factor is topography such as a hill or mountain which may reduce the incidence of direct sunlight hours; similarly, the presence of a building can create atypical shade conditions. For example, a structure facing south will have markedly different shade conditions to the north and south.