Light Quality Consideration – Four Different Types of Shade
Sunlight is essential because it is absorbed by chlorophyll in the plant cells and converts moisture absorbed through the roots and carbon dioxide absorbed through the leaves into sugar and water. This vital food-making process is known as photosynthesis. Generally, the sunnier a plant’s position the more it reaches its full potential, but there are many notable exceptions. Thousands of plants have adapted to various kinds of shade. You only have to consider the darkness of a jungle floor and the abundance of lush vegetation growing there to realize how successful these plants are. Indeed, far from restricting choice, shade pro¬vides plenty of planting options and the chance to create a contrasting area of garden. It makes an ex¬cellent foil to bright areas with hot colours, so much so that, in a large, open, sunny garden it is worth planting a small tree simply to create an area of shade.
Types of shade
Before completing a garden design, and certainly before planting, assess what kind of shade you have. The degree varies according to the amount of light re¬ceived, which itself is dependent on the time of year.
Dappled shade – This is thrown by the leaf canopy of trees overhead. It can be quite cool and dense in summer but non-existent in winter. This creates good woodland conditions where spring flowers bloom in full light before the tree foliage emerges, followed by a summer in cool shade.
Partial shade – Such shade is created when an area is in shadow for part of the day and receives direct sunlight at other times. A wall or building is the most likely cause. The further the site is from the equator, the lower the sun in winter, so that in London or Oslo, New York or Chicago, such obstacles throw more shadow than in Rome, Madrid or Los Angeles. This makes no difference in mid-winter but has a consider¬able influence in spring, when even as little as an hour of direct sunshine is sufficient to tempt a crocus or an aconite into bloom.
Full shade – Full shade refers to an area which is always in shadow but which, nevertheless, has enough diffused daylight to support a reasonable plant collection. For example, the space between two buildings might be in constant shadow, as would the area of ground directly behind a wall running east to west (this, in turn, produces a cooler microclimate).
Dense shade – This type of shade is the most likely to cause problems. There may appear to be too much gloom to grow anything but the dullest evergreen which even then languishes and looks miserable. But even dense shade is plantable.
The most challenging problem is dense, dry shade where surrounding buildings also restrict the amount of rainfall. Although there are plants that will cope with such surroundings, they seldom look as good as when growing in more suitable locations. There are, however, ways of minimizing the disadvantages. Con¬tainer-grown plants can be moved here for a number of hours each day, provided at other times they get plenty of sun. Another good choice is spring bulbs which have their own food supplies and flower well in their first season even in the densest shade, but they must be replaced each year since they are unlikely to bloom again. Improving the soil to minimize moisture loss and maximize fertility will also help.
Tags: bright areas, choice shade, colours, jungle floor, leaves, lush vegetation, mid winter, partial shade, photosynthesis, plant cells, plants, spring flowers, sunny garden, tree foliage, vital food