The many climatic variations in your garden are called microclimates. Structures, existing plants, exposure to the sun, and elevation differences combine to create these small climates. For example, a cool, shady microclimate may be found on the north side of a house, a hot one in an unprotected southwestern comer, a cold one in a hollow at the bottom of a hill, a humid one near a dense planting of shrubs, and so on. Differences in microclimates affect many aspects of gardening. For instance, you may find that your daffodils bloom several days earlier than those in a neighboring garden, and your maples may not change color as quickly in the fall.
Microclimates change with time. On a new home site, the only shade may be beneath overhangs, under the patio roof, and in the northern exposure. As plants grow, so does the amount of shade. Plant growth also affects the temperature, wind pattern, humidity, and other elements that make up microclimates. The most successful gardeners are acquainted with all the different climates in their gardens. Before you buy any new plants, take an inventory of your microclimates. You will be able to choose plants best adapted to the general climate. For example, you may be able to stretch a plant’s adaptation by a zone or even two zones if you place the plant in a warm, protected spot.