by Joan McIntyre
NOVA Natives are not only cool but can help keep you cooler in summer (or warmer in the winter). When strategically placed shade trees along with shrubs, vines, grasses, and ground cover can cool the urban environment and save up to 40 percent on energy bills. One study found that shading can reduce surface temperature on walls and roofs by as much as 45oF, which in turn reduces the heat transmitted into buildings and the surrounding atmosphere. Here are some ways to layer your landscape with native trees, shrubs, and perennials to be more comfortable, save money, and support native wildlife.
Stately canopy trees such as Sweetgum, Tulip Tree, Hickory and Oak, reaching upwards of 100 feet, can provide excellent shade for east and west-facing sides of your home. Such deciduous trees planted on the south side will also help lower temperatures while letting warming sun through during the winter months. Trees should be planted far enough away (typically 15 feet) to keep roots from damaging foundations. While trees may take 10 years or more to have the full impact, it’s an investment worth waiting for.
Add diverse layers of native understory trees, shrubs, and perennials around your home to shade walls and windows to further cool your home, leaving enough room (about a foot) for air circulation once plants are mature. Vines such as Coral Honeysuckle, Crossvine, and Passionflower on trellises can quickly offer shade and work for smaller areas. A vine-covered arbor or pergola will make your patio a cooler respite from the heat. Shading your air conditioner with native trees and shrubs will make it run more efficiently during peak periods.
Create a wind barrier with layers of native trees and shrubs along north and western facing to reduce the chilling affects of prevailing winter winds and keep your home warmer. Native evergreens such as American Holly, Eastern Red Cedar, and Sweetbay Magnolia make good choices. Multiple layers of trees and shrubs will block wind at ground level as well as higher elevation, be more visually appealing and provide more benefit to local wildlife. To be effective a windbreak should be at a distance of two to five times the height of the trees when mature. For small yards, evergreen shrubs such as Inkberry Holly or Mountain Laurel can be planted next to the house to create a dead space for extra insulation or shelter doors exposed to the wind.