Have you ever been busily typing away, only to discover that what you've just typed is gibberish? In disbelief, you look down at your hands resting on the keyboard and, sure enough, one of them isn't lined up with the proper keys. Due to a temporary lapse in concentration, your location is all wrong. Consequently, even though you know how to type and your fingers were making all the right moves, the result is not at all what you wanted. Well, so it is with growing plants, too....
Site selection is critical when growing plants. Most people are aware of one criterion for site selection: namely, a plant's tolerance for sun or shade. But site selection can become more complex than simply growing full-sun plants in the sun and shade-loving plants in shady nooks.
For instance, site selection for trees and shrubs should take into account the conditions they'll have to face when winter arrives. It's counter-intuitive, perhaps, but a southerly exposure for some trees and shrubs can be detrimental in winter. The sun on a bright winter's day warms up their plant tissues, fooling them into action at the cellular level. Then, when the sun goes in again, the quick drop in temperature can cause injury, manifested in splitting along the trunk.
Certain evergreens are highly susceptible to this problem. Learn which plants are most susceptible and avoid a southerly exposure for them when it comes time for site selection. Commonly-grown evergreens that are susceptible are:
As a precaution, do not install the above plants on the south side of buildings. If it's too late, and you witness splitting on the trunk, apply tree wrap.
Conversely, perennial flowers may prosper from having a southerly exposure, which results in a "microclimate." For instance, perennials planted up against a house, garage, shed, or fence with southerly exposure are growing in a space that may stay a few degrees warmer than most other places in the same yard. As a result, you may even get away with growing a perennial not meant for your zone in such a microclimate (for instance, a perennial listed for planting zone 6, even though you garden in planting zone 5).