Strategic landscaping can help your energy conservation efforts. A mature shade tree, for example, can equal 10,000 BTUs of cooling as it absorbs solar radiation. The west side of the house will benefit the most from shading since it takes the brunt of the hot afternoon sun.
Trees that shed their leaves in the fall are especially "solar friendly." They cool the house in summer, then let the sun shine through bare branches to warm it in winter. A tree with a broad canopy will give the most shade but be sure to consider factors like utility lines and other space limitations. Sometimes columnar trees like Bradford pears are more practical.
Vines are often used for shading in the hot climates of the Mediterranean and Latin America. Bougainvillea, roses, clematis, honeysuckle, trumpet vines and jasmine are some of the choices seen draped over the top of windows. Train one or more vines up the side of the window then drape them across the top of the sash. Prune as needed and let the runners develop lateral branches to increase shading.
Some plants provide shade in summer, then die back completely, are annual castor beans and sunflowers, as well as tall cannas, which come back each year and usually multiply over time. Stands of these type plants will shade the windows and sides of your house. A shade tree, once established, can cool the roof, too. A good strategy would be to plant a shade tree for the long term and use these shorter-term fixes to fill in while the shade tree develops.
Rosemary Moyers, Smith County Master Gardener
Texas Cooperative Extension
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