GROW: Landscaping for energy conservation

By Kimberly Toscano

When you are planning your landscape, it’s likely you’re only thinking about the various colors, textures and overall look you’re hoping to achieve.

However, one reason to plant trees and shrubs around the house may not immediately come to mind, and that would be the benefit landscaping has on energy savings. Well-placed trees and shrubs can help reduce heating and cooling costs. Factors to consider when planning the landscape are the angle of the sun, orientation of the house and direction of winter and summer winds.

We all know those Oklahoma summers can be pretty brutal. Providing shade can significantly reduce the heat flow into a home, which in turn can help reduce your energy bills. Studies suggest shade can reduce heat flow by as much as two-thirds. Likewise, shading roofs with tall, high-branching trees such as oaks, can help with cooling. While summer shade is desired to reduce cooling expenses, we also want to maximize winter sun. To get the best of both worlds requires careful tree selection.

Characteristics to look for include high branches to block summer sun, but permit winter sun, which strikes the house at a much lower angle. Open branching such as that of the Kentucky coffeetree allows for a more open winter canopy and allows greater winter sun penetration.

Homeowners also want to consider the timing of leaf drop. Ideally, look for trees that drop leaves between Oct. 15 and Nov. 15. You may want to avoid trees with cone-shaped crowns, such as pin oaks and many evergreens because they provide significantly less shade in summer and block winter sunlight. Consider shading south and west facing walls, which capture a great deal of heat from the hot afternoon sun during those dog days of summer.

Wind is another consideration in landscaping to conserve energy. Your home can lose much more heat on cold, windy days than on cold, calm days. Well-placed trees and shrubs can intercept winter winds and reduce heat loss. Try to identify the direction of winter winds in your area. I know this can be hard because those Oklahoma winds seem to come from all directions at times. Typically, however, the coldest winds arrive from the north and northwest and so a windbreak is best located along the north and west edge of your property.

Foundation plantings are the plant materials placed along the perimeter of the home and impact the energy gain and loss from a home in a variety of ways. They act as insulation against wind, reducing air currents close to the home. They also create pockets of air that act to insulate the home. As with wind breaks, evergreens have a greater impact on energy savings than deciduous plants.