When the weather is this warm, it is good to have at least some shade in the garden. Shade trees or structures make working in and enjoying the garden much more comfortable. Too much shade however, can be detrimental to many plants which prefer full sun exposure. Fortunately, there are many species which are well suited to shady conditions.
Most trees which grow well in shade are “understory” trees. This means that in their natural habitat, they grow under the canopies of much taller trees. Some larger species may be understory trees when young, but will also grow in full sun exposure if they eventually get past the taller trees. Although shrubs, perennials and vines which also grow in part shade are not classified as understory species, most are also accustomed to sharing their natural habitat with the other larger plants and trees.
Incidentally, many vines which grow in shade are real social climbers. Ivy for example grows at ground level at it’s juvenile phase as it would in a forest. When it encounters a tree, it clings to the trunk and uses it for support; a horticulturally adolescent phase. When it reaches the top of it’s host tree, it begins to produce adult growth which supports itself. Adult growth blooms and produces seed. Eventually, the ivy shades out the host tree and may kill it. By the time the tree falls, the ivy has produced more than enough seed to ensure the continued survival of it’s species. (Adult growth may appear on ivy planted in full sun, because it thinks it has already reached the top of the forest canopy.)
When gardening in the shade of larger trees, fences or buildings, it is futile to use plant species which require full sun exposure. There is such variety among those which prefer shade. As new landscapes mature and trees grow, some areas become shadier, increasing the necessity of such plants.
Exposures to the south and west are the hottest. Heat and glare (reflected sunlight) is enhanced by concrete pavement and lighter colored paint on walls and fences. For trees, reflective roofing material is also a concern. From experience in my home, I know that enough of these surfaces can even cause difficulty on an eastern exposure.
More glare is absorbed as plants grow and increase foliar surface area. In some situations, less tolerant species may eventually be added, especially if maturing shade trees are present. With good planning, extreme exposure should be no more of a problem than minimal exposure.
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