Microclimates are small (relatively) areas in the landscape that have conditions which differ from the overall climate of a region. It is basically climate on a small scale! Taking advantage of the different microclimates that exist on your property will allow you to expand and diversify your landscape plan. Sometimes they allow you to grow plants that are normally not hardy in your area.
Microclimates can affect any element of climate: temperature, light, moisture, humidity, or wind. They can be either naturally occurring or artificially created. For example:
A naturally occurring microclimate can be found under the shade of trees. In areas with hot humid summers, it is often preferable to plant sun perennials in a location that receives a bit more shade than is normally recommended, especially if the shade protects the plants from the hot afternoon sun.
In winter, a southern exposure usually becomes shaded by 3 o'clock in the afternoon. This shade causes the air temperature to decrease gradually through the afternoon and evening. In contrast, an area with a southwestern exposure normally receives no afternoon shade and therefore, when the sun sets, the temperature drop is radical and fast. In this situation, winter injury of plants is more likely to occur especially with evergreens.
A northern, northeastern, or southeastern exposure that is protected from wind is a great location for broadleaf evergreens such as Holly, Azalea, Rhododendron, Pieris, and Mountain Laurel. Winter winds can be a major problem for these evergreens because they increase water loss through the leaves which can cause winterkill or burning of the foliage. To protect against winterkill, apply a 3" blanket of mulch and remember to irrigate during periods of dry weather when the soil is not frozen. Another safe guard is to spray your evergreens with Bonide Wilt Stop, a natural, organic anti-desiccant which will protect them all winter.
The most important advice is to try and choose the right plants for all areas of your landscape. Take the time to note the patterns and timing of sun and shade, the direction of prevailing winds, the areas where frost is slow to melt, and other factors related to microclimate.