House & Home: Landscaping for energy efficiency

By James Dulley

…and trouble-shooting a leaky toilet.
by James Dulley
Dear Jim: I want to landscape my front yard and around my deck with decorative evergreen and flowering dwarf shrubs. What types are available and where should I locate them for the greatest energy efficiency?
Larry P.

There are hundreds of decorative evergreen and deciduous (drops leaves in fall) dwarf shrubs. Foliage colors, flowers, berries and shapes vary considerably. By planting a variety of dwarf shrubs, the attractive colors and textures change throughout the year.

Dwarf shrubs are ideal for energy-efficient landscaping because they remain small at maturity (2 to 3 feet high). Plant some near the house foundation and some further away for windbreak ramps. Since they stay small, they require little care.

Many dwarf shrubs have flowers, small fruits for wildlife and beautiful autumn coloration. Some deciduous varieties also have ornamental bark or branching habits that are attractive in the winter too.

Dwarf shrubs can cut your utility bills year-round. The sillplate on the foundation is the area of greatest air leakage into most homes. Planting dwarf shrubs near the house, especially evergreen varieties, can block the force of the cold winter winds and reduce this leakage.

As a windbreak ramp, dwarf shrubs can be planted to the northwest side of taller shrubs and trees. These begin directing the cold winds upward toward the taller trees. The upward wind path continues over the top of your home.

In the summer, dwarf shrubs cool the air near your house with shade and by a process called transpiration. As plants give off moisture to the air, the air cools. This is a similar process to the way perspiring cools you. The air temperature can be as much as 10 degrees cooler by the shrubs.

Dense-foliage deciduous dwarf shrubs are ideal for summer heat control. Plant an area of dwarf shrubs near your house on the south and west sides to create a cooling buffer. This buffer blocks the indirect heat radiating from hot patios, sidewalks and driveways.

Dwarf shrubs are often more expensive than other types of common fast-growing larger shrubs. However, since the shrubs maintain their initial size, you will not have to relandscape every several years. Cheaper common shrubs look great when they are small, but can quickly outgrow the space.

When selecting dwarf shrubs, always consider the "hardiness zone" of each shrub. Hardiness relates to the coldest winter temperature which it can withstand and other area-specific conditions.


Dear Jim: My parents' yard has trees and their air conditioner seemed to run less than ours last summer. I know it takes years for trees to grow, but can you give me some tips on where and what kind to plant in our yard?
Sandra H.

It is not just your imagination; your parents' air conditioner runs less because of the trees in their yard. The Department of Energy (DOE) has done sophisticated computer models showing just three properly placed trees can cut your utility bills by up to $250 per year.

There are many other benefits from landscaping your yard with the proper type and placement of trees. By shading your house, the walls, shingles, even indoor curtains will last longer because the sun's rays are blocked. The air immediately around your home will be less polluted and the oxygen level  higher. Trees also create a sound barrier from road noise.

The key to efficient landscaping is selecting the proper species and placing them in the proper location for your specific climate. A well-landscaped yard in the hot, dry Southwest will look totally different from one in humid Georgia or in the Plains.

Draw a layout of your yard and decide where you need trees for your climate type. Also determine the height, shape, type (evergreen or deciduous), and growth rate of the trees. Next, talk with a local garden store expert to make sure you are planting trees which will thrive in your climate zone.

In a temperate climate, you will also be concerned about winter heating bills. Plant deciduous trees on south and west leaving a small gap to the southwest for breezes. During winter with the leaves down, the sun will shine through. Plant evergreens on the north side for a winter windbreak.

In hot, dry climates, planting trees to shade the walls and roof is critical. Tall trees with a high canopy are effective. Lower plantings placed near the house are good because, with the dry air, the evapotranspiration process can create significant cooling.

Dear Jim: I noticed damp spots on the ceiling below the second-floor bathroom. They are directly under the toilet. I have checked and the toilet is not leaking or running. What is the source of the spots?
John K.

Dear John: There can be many sources for the spots because water will run along joists and drip off the lowest point often far from the source. Since they are under the toilet, that is the first possible source to check.

Most likely, the wax ring where the toilet rests over the drain pipe is leaky. This will happen over time, especially if the toilet is not bolted tightly to the floor. Replace the wax ring and see if that fixes the problem. 

Download (from Update Bulletin No. 701 listing 100 types of deciduous, flowering and evergreen dwarf shrubs, hardiness zones, height at maturity, growth rate, habits and hardiness zone map of the U.S. Update Bulletin No. 438 shows diagrams of landscaping layouts for four climates, selector guide of 100 trees listing heights and shapes, growth rates, hardiness zones, and tree care/pruning tips. $3 each. Send questions to James Dulley c/o

This article was originally published on February 28, 2007.