Unfortunately, I just had to have a gigantic oak tree removed from the south side of my property. Before removal, we happily gardened and lounged barefoot in the backyard all day long – in the shade of said tree. Now, the ground burns our feet and the sun scorches our skin. My hammock, once graced for an afternoon cat nap daily, is now in my laundry room. Hot, hot, hot. I can’t wait for my small but fast growing fruit tree to cast enough shade to sit beneath.
The increase in sunlight wasn’t a surprise. I understand the basic physics of sunshine and shade. What shocked me was the increased temperature. I couldn’t imagine in my wildest dreams that the thermometer would soar to almost 20 degrees hotter.
How Do Trees Keep Cool?
A tree is a living organism. It has the same basic needs as a human – air, water, food, and shelter. It just meets these needs a bit differently. Instead of breathing with lungs, a tree transpires. Water vapor is released into the atmosphere from their leaves. As a result, the surrounding air is cooled. Shade below, water vapor above… It’s a double whammy for air cooling.
This cooled air is wonderful over a hammock or playground, but what about over the roads? That pavement gets hot enough to cook an egg! And it stays hot. I dread having to wrestle my toddler in and out of the car seat in a hot parking lot. It’s no wonder that I pray for a big oak tree to park under. A shaded surface can be 20-45*F cooler than an unshaded surface. That’s a huge difference!
Want to Lower Your AC Bill?
Trees should be planted on the south, west and east sides of your home for maximum cooling. Specifically the southeast and southwest sides. Unless you have a tree or structure, you won’t ever have shade on the south side of your house. The sun’s rays are strongest in the afternoon from the west, and the morning sun streams into your windows from the east to heat the house up early. For maximum summer shade, plant the taller trees to the east and west sides of your home, and tall shrubs on the south side to shade walls and windows. Bamboo is also an option, but please purchase it from a reputable vendor to avoid getting running bamboo. The clumping variety will stay in one place better, spreading in a cluster rather than randomly through your yard and neighborhood.
You want to plant near enough to your home to shade the house, patio and yard, but far enough away to avoid roots damaging the foundation. Leave at least three feet of space between your home and any shrubs to allow for airflow. Larger trees will obviously cast more shade while shrubs will cast less, but their growth pattern forms a wall of shade, good for near a house or patio.
Always consider the mature size of a plant. Just because it’s 6 feet tall now, doesn’t mean it’ll stay that size – it’s roots will grow too! Large trees should be planted at least 20 feet from your home. Don’t forget to call 811 for the location of underground utility lines.
In addition to trees, vines on trellises or pergolas will grow quickly and cast shade. In Florida, you shouldn’t allow vines to grow on your house; it can damage the exterior and lead to other problems down the road. Groundcovers rather than rock or concrete can cool the ground up to 10 degrees. I have a small concrete patio with rocks next to it and have noticed this area is super toasty. I’m swapping the rocks out for a native groundcover that doesn’t need to be mown and put a tall potted plant nearby to shade the patio.
Make a Plan
With a thoughtful arrangement of trees, shrubs and groundcovers, you can really lower the temperature of your yard, home and surroundings. Imagine if all of your neighbors did the same – cooler street, cooler breezes! It’d be an oasis in this subtropical sauna of a Florida summer we’ve been having!