A bit of wisdom about gardening arrived in the mail the other day from one of those TV-based do-it-yourselfers.

It read: "The key to successful gardening, is placing plants where they will grow."

I was taken aback, since I've spent my life trying to grow sunflowers in full shade and wondering why nothing ever happened.

OK, I'm being facetious, but no matter how desperate you are for publicity, you need not state the obvious. This is a nation where most people still can't program a VCR, but even the novice gardener knows that you need to plant sun-loving plants where the sun shines.

Speaking of publicity, in my book, What No One Ever Tells You About Renovating Your House , I devote the final chapter to landscaping.

The fact that it is the last chapter, shouldn't detract from the importance I place on landscaping adding to the value of your house.

When you put the house up for sale, its curb appeal is critical to getting the prospective buyer out of the car, and to the front door to see what is inside. When you add on to your house, landscaping is a relatively inexpensive, yet cost-effective way to tie the new and old seamlessly together.

Landscaping is more than just being pretty. It has environmental implications that are far more important than just a nice looking front yard.

In the days before air conditioning, houses were designed to take fullest advantage of natural heating and cooling: wide eaves, deep porches often screened in and used for nighttime sleeping; thick walls to provide thermal-mass insulation; metal roofs that reflect the sunlight; and attics and high ceilings.

Landscaping was designed to maximize summer shade and breezes. Deciduous trees around the house would keep the house cooler in summer, then shed their leaves in the fall to maximize available sunlight in winter to keep the house warmer.

This was something that builders of post-World War II houses didn't quite get. They denuded the landscape of trees in favor of vast stretches of lawn, concrete, and asphalt. They planted easy-to-maintain evergreens that, of course, don't shed leaves in the winter, creating spots in houses that never get warm, no matter how high you raise the thermostat.

Of course, builders assumed that energy would be cheap forever, but even after the events of the 1970s, a lot of builders still didn't understand the importance of landscaping.

These days, government and the builders themselves are making an effort to limit the environmental impact of residential construction, and the role that landscaping can play in it.

Fewer trees are being turned into mulch these days, as builders make a altruistic stab at preservation.

One of the more important changes in how we view landscaping, is what is known as xeriscaping, but simply, as the TV-based do-it-yourselfer pointed out, putting the right plant in the right place.

Here's the problem: Native species have long since taken a back seat to exotic plants in landscaping. Gardeners seem to take great satisfaction in getting such exotica to bloom, even though those efforts are usually time-consuming and labor-intensive.

In addition to the challenge involved, gardeners have tended to lock on, to what is popular at any given moment.

While such exotic plants are indeed beautiful, they may, in the long-term, harm the environment. For example, Japanese knotweed, which grows 10 to 12 feet a year, can pull down a native maple or create enough shade to kill anything that tries to grow below it. Japanese honeysuckle, grape ivy, and the multiflora rose also are a threat. And Norway maples are creating a "monoculture," by crowding out native beech and poplar.

The landscape industry has grown so much that virtually all residences and commercial sites, use their products or services to some extent. Plants are often selected from a narrow range of exotic species that require intensive maintenance.

For the Southwest, that means water, which may be coming down in buckets this year, but is generally in short supply.

The solution: xeriscaping, or favoring native species over the exotic ones that place a strain on the ecosystem. These native species have adapted to the stresses, and strains of the local climate and have learned to survive. If there is a drought, they adapt. If there is too much rain, they adapt.

Sagebrush may not be as pretty as honeysuckle, but at least it belongs.

So planting the right plant in the right place doesn't seem so out of place, now does it.