Landscape Air Conditioning Into Our Homes

mandevilla vine for landscape color and covering

Air conditioning is available from the nurseryman as well as from the electrician. If we plan our landscaping with that in mind, we can lower the temperature inside our homes on a hot summer day by several degrees. Shrubs, vines, trees, and grass all may be used in the air conditioning process.

The brick, stone, stucco, and glass of our houses, the pavement or flagstones, streets, walks, patios, and even the bare earth all act as stoves using the sun’s rays as their source of heat.

We can materially modify the heating effect by planting to keep them in the shade. Since this outdoor air conditioning also calls for free movement of air, we need to think about low growing shrubs and high-branching trees.

Planting a Cool Room

Planting for a cool home need not detract from the landscape designed for appearance. In both instances, start with a good turf and some grass that grows in shade under trees.

A vigorous growth of grass allowed to stand two to three inches high gives vastly more cooling power than does a lawn scantily protected from the blistering sun by closely cropped, thin sod.

For a thick, lush lawn, a good seed bed preparation, proper fertilization, and judicious lawn watering are needed.

Close clipping will pretty well nullify the watering and fertilizing. To get the most coolness out of a lawn adjust the lawn mower to cut not less than two inches high and preferably two and a half or three especially in hot, dry weather.

Water is important, not only to maintain a good turf to shade the ground, but also to maintain the cooling effect of evaporation. It is the same principle as the air conditioners used in arid regions, that depend on evaporation for their cooling effect.

All of the plants growing about our homes pick up moisture from the soil and give it off by evaporation through their leaves.


Since we can’t use grass on walks, streets and landscaped patios, we must depend on trees and vines. We have all experienced the effect of driving suddenly from the blistering heat of a business area, with its unprotected pavements and brick buildings, into a residential area with large trees arching over the streets.

The cooler temperature in the residential area is quite marked. The trees and grass are largely responsible.

Trees should be located to give maximum protection from the sun on the southeast, south and west exposures of our homes. In mid-summer the sun is nearly overhead at noon. The tree that protects the south side of the house must, therefore, be rather close to it and considerably taller than the house.

Personally. I do not see as much objection to a small house nestling in the protection of a sizable tree as do some people.

Especially should we attempt to shade our windows. Our grandparents solved the problem through the use of the old-fashioned shutters. We can get somewhat the same effect with the right kind of trees. A tremendous amount of heat enters through glass exposed to the sun… even double paned windows.

Vines Play a Part

It is not easy to maintain shade from trees on the entire wall surface of a house. This is where vines enter the picture. We need only touch a sun-baked brick or stucco wall and then feel under the leaves of one that has a wine growing on it to be convinced of the insulating effect of vines.

Boston ivy is excellent for the purpose. If a more vigorous and somewhat coarser vine is acceptable, our native Virginia creeper will serve admirably.

Others that may be mentioned are the trumpet vine and winter creeper. By including those that need a trellis or framework on which to grow, we have an extensive list.

The various forms of clematis, some of the climbing roses, passion vine, honeysuckle, and bitter-sweet are but a few of those that may be used,

The plants used should protect us from sun without interfering with the movement of air near the earth’s surface. Low growing branches on trees are usually objectionable for this reason. Some of the standard shade trees are naturally high branching; others may be pruned to meet this requirement.

The hard maples, elms, and many of the oaks are good, Less common are the sweet gum and tulip tree. The latter is a rather quick growing tree. Likewise, the white ash and thornless honey locust will give rather quick shade.

The locust does not give as dense a shade as some of the others, However, it will serve the purpose of cooling the air. Other desirable trees are the yellowwood. Kentucky coffee tree, sour gum, and the Chinese scholar tree,

Best Insulating Effect

In determining where to plant trees for best insulating effect, we should observe the position of the sun above the house over an entire season before digging any holes.

A large tree at a considerable distance from the house will break the early morning sun. By mid-morning the sun is high enough that a tree of the same height must be much closer to the house to provide the desired shade, and at mid-day the tree must be very close indeed, perhaps within 12 or 15 feet.

tree lined drive

A good tree for the south side of the house is the hickory. The high branches give adequate protection against the sun and still allow for a free movement of air. The tough wood does not break easily.

Another tree that can be planted close to the house with little danger of a limp damaging a roof is the Osage orange, Although it is little used, it has more possibilities as a shade tree than is usually accorded it.

To protect the house from afternoon sun trees are needed on the west side of the house. As the sun swings farther to the northwest and gets lower in the sky, we can use lower growing trees farther from the house.

Trees in the neighborhood outside ones own yard are also helpful in tempering the summer heat. Trees in the direction from which the prevailing wind comes are quite effective.

A breeze coming through and under trees, and over a good sod will be degrees cooler than one coming over unprotected areas. The ideal situation, rarely attainable, would be to have a large open grove of trees to the south and west.

Concrete, flagstone and brick patios can be the source of unwanted heat if exposed to direct rays of the sun.

Either a tree may be planted to shade it, or a framework may be provided with vines growing over it. Innumerable vines may be used in such a location. A favorite one is the wisteria.

For summer insulation it is best to use deciduous trees and vines… the leaf shedding kind …rather than evergreen.

We don’t want shade in the wintertime. Instead we need the warmth and light of the sun. Especially during rainy spells in the spring, we like to get all of the light and air that we can around our houses.

Image: Jeff Leigh

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