One of the first things I do when I look at a landscape or garden is to determine direction. Direction tells me not only how the sun will affect my home and garden, but also from which area prevailing winds will blow. These two factors are key to designing a workable landscape that integrates both the house and garden. As a homeowner, I want my home to be sheltered from the sun's hottest rays in the east and west in the summer, while taking advantage of the southern rays in the winter. I also want to have a windbreak on the northern side of my home, and shade on the east and west sides of my home in the summertime without blocking the cooling western breezes.
We all know in the winter time the angle of the sun is lower. Southern facing windows will get the benefit of what light there is available. The northern side of our home will get no direct sun during the winter. East and west will get some sun, though the rays will not be as strong as in the summer. If you plan to plant trees around your home, make sure the trees on the southern side of your home are deciduous so light can come through in the wintertime. Deciduous or evergreen trees work equally well on the east and west sides of your home. On the north side of your home you might try evergreen trees such as cedars. Cedars can effectively block the cold northern wind. Just be sure they are not planted so close to your home they pose a danger of falling in too strong winds or when bogged down by ice and snow.
Summertime is when we get the hottest and most direct sunlight because the earth is tilted so that the northern hemisphere is closest to the sun. Additionally, the sun will be pretty much directly overhead. The south facing side of our home is not going to take a direct onslaught of the sun's rays. Planting trees on this side of your home to block the sun's rays is not necessary to block the high summer sun. They may help with the spring and fall sun, but a common misconception is that the south is always the hottest and sunniest so plant trees there. Not true.
The western side of your home will be the hottest side of your home in the summertime. Just ask anyone who has a patio on the west side of their home with no trees to shade that patio how often they use it in the summer. I'll wager that if they ever use it, it is early in the morning or after the sun has set. The eastern side of your home will also be hot, but not as hot as the west side since the earth does take a while to heat up after the night. You can expect that just about anything you plant on the eastern side of your home in Tennessee is going to do well, whether it requires full sun or part shade. Both are provided for on the eastern side of a house. But, because of our intense heat and sometime (more often than not) droughts, you need to be careful when siting plants on the west side of your home when there is no protection there. Just because a plant says 'full sun', does not mean it likes eight hours of direct western sun.
Here in Tennessee prevailing winds blow from the south and west in the summer. In winter, the winds blow from the north and northwest. Why is this important? Prevailing winds are going to be the strongest and most lengthy winds and are apt to cause damage to plants. Especially newly planted trees and shrubs, and also to tall vegetable plants like tomatoes and peppers and even vining crops if you have them growing on a trellis. Try to consider how prevailing winds will affect plants when siting your plants and placing trees so as to not block the cooling winds in the summertime. In my garden I try to plant stronger plants into the wind with the less strong on the leeward side. I also try to have strong trees in groups into the wind in order to protect trees closer to my home. You really don't want one little or big tree 30 feet from your home on the west side. You are just asking for trouble. Plant groups of trees keeping in mind their ultimate size and required spacing out further from your home to protect those trees close to your home.
The next time you are in the garden consider all the patterns, shady and windy and plan your garden accordingly for long term pleasure and workability.
in the garden....