A gardening professional speaking at a conference stated that just about every yard has a unique micro-climate. Micro-climate means that a unique climatic condition is created by buildings, house location on the lot, wall location, berms, and other factors that are a little different in most every location. Knowing and observing the climatic conditions in your yard will help you place appropriate plants in locations where they will thrive vs. another area in the yard where they may struggle.  For instance, knowing where the prevailing winds strike your yard would help you choose a location away from a windy location for a tender plant.

Another topic that gets a lot of discussion is borderline plant hardiness. The micro-climate in the yard may allow you to successfully plant a zone 6 plant in a zone 5 location. Placing the zone 6 plant in a protected area of the yard that is sheltered from the north wind and where it gets more heat from a southerly exposure to the sun will very likely allow the plant to be grown successfully. A good rule to follow would be is "don't fight your site". You will save time, money and energy by working with your micro-climate rather than fighting it.