Shade trees give your air conditioner (& wallet) a break
Mexican Sycamores, sturdy Texas Elms, and majestic Live Oaks do more than beautify landscapes. “Properly placed shade trees can help reduce energy usage in the home, thereby improving efficiency and saving money on heating and cooling bills. Trees, as part of a landscaped lot, also add to the overall home value,” says Tim Mace, communications director at Austin Tree Services. How much energy can tree actually save your home? The U.S. Department of Energy reveals that strategically placed trees can reduce home energy use by as much as 30 percent. Trees offer other environmental benefits, too: reducing air pollution, improving soil and water quality, and more.
When you go to a nursery to pick out the types of trees you want to plant, have an idea of what you want for your yard—like what area you want to shade or what type of soil you have. “Considering your specific circumstances is a crucial step in determining the right shade tree for your yard,” says Liza Williams, garden center manager at a nursery in Austin. “Always keep in mind the space you have available, and what the growing conditions will be like. Some trees can tolerate very wet areas, but most prefer to have moist, well-drained soil.”
Types of shade trees
Williams recommends several types of shade trees that are a great fit for Texas homes:
- Texas Redbud. This small, graceful native Texas tree provides food/shelter for bees, butterflies, and birds. Texas Redbud provides three landscape interests: an explosion of very colorful flowers in early spring, the foliage turns deep gold and red in the fall, purple seedpods appear during the winter.
- Nuttall Oak. This fast-growing tree thrives in drier areas, so if you have a lawn that doesn’t get overly damp, this is a good option. It’s a relatively new species whose leaves turn brilliant red in the fall.
- Chinese Pistache. Towering at about 35 feet tall, these trees are naturally pest and drought resistant, making them good for particularly hot, dry summers.
- Crape Myrtle. A common favorite that grows best in the South, Crape Myrtle trees can reach 20 to 30 feet, flowering from midsummer to fall with white clusters of flowers and brown fruit, which will persist through the winter. Natchez, Sioux, and Tonto species tend to have great selections.
- Sugar Maple. This is the perfect tree for Northern transplants craving New England autumns. The Legacy cultivar is particularly suited for Southern heat, still providing an attractive, dense canopy whose leaves turn a strong, clean orange-yellow in the fall.
When a tree is planted, a new habitat is created, not only for birds and wildlife but also for shade-tolerant shrubs that thrive underneath the canopy. Here are some species to consider:
- Hydrangeas produce striking blooms even if exposed to filtered light and not in deep shade. A lot of varieties will change color depending on the acidity or alkalinity of the soil. The average size is about 5 feet in width and height.
- Hostas are a perennial shrub that does great in the shade and can still maintain their dual-tone leaves. When planted in areas like the South, where winters are less severe, they may not die back for the winter. They can range in size from 1-5 feet, depending on the variety.
- Arrowwood viburnum can tolerate partial shade when planted even though it can be found in deep woods naturally. Can be quite showy with its creamy white flowers in the late spring and dark-blue fruit in the late summer. This is a larger shrub, at 6-12 feet.
- Oregon grape holly is a smaller shrub, ranging from 3-6 feet, that can grow in full shade. It is evergreen and has the typical holly leaves but takes on a purplish tone in the late fall and winter. Always an ornamental addition to the landscape, it has fragrant bright flowers in mid-spring and black grape-like fruit in the summer.
- Hummingbird sage is a type of salvia that can grow up to 2 feet tall as it spreads over the ground. Its showy, deep- rose-pink flowers grow on 30-inch flower stalks. It attracts lots of butterflies and pollinators and does very well in the dry shade of oaks.
Mace recommends planting your tree during the fall. “This is the time of greatest root growth and also gives the plant time to establish before going through the heat of summer.” If you plant in the summer, watering should be done in the early morning or late evening. Watering in mid-day heat can cause leaves to be scorched.
When it comes time to plant a tree, the hole should be dug about twice the size of the root ball or container to give its roots room to grow. Place rocks in the bottom of the hole to allow water to drain from the roots—because although trees love water, they do not like to sit in it.
Soil content can impact the success of newly planted trees. Some trees prefer low-pH (acidic) soils, while others take to higher-pH (alkaline) soils. For this reason, it is always a good idea to add some topsoil or compost to the soil in areas that contain less-suitable soils, like clay or rocky soils.
Care and maintenance
For newly planted trees, watering should be more frequent, keeping the soil moist but not wet. Add mulch around trees to help retain moisture. In moderation, fertilizing is a good idea to help trees get established. As a rule, Mace says, “you will need to thoroughly water the root ball of the tree one to two times a week during the growing season—from spring to fall.”
Make sure to keep trees trimmed to help prevent drooping, decrease the weight of the branches, and control the shape of the tree. Staking can not only prevent trees from blowing over in the heavy wind, but it can also train them to grow straight upward, instead of at an angle.
Keep in mind that if you are planting for energy savings or shade, this will happen over time and won’t be instantaneous. It could take a few years to see significant impacts, but the benefit is well