In the torrid Southwest, a swaying palm tree brings instant oasis

As the setting sun turns the sky to a golden hue, stately palm trees sway gently in the evening breeze. This may seem like the description of some isolated tropical island, but it could just as easily be applied to almost any desert community in southern Arizona.

Newcomers to the American Southwest are often surprised to find the streets of major cities lined with a variety of palm trees, some of them stretching to a height of 60 feet or more.

Several of these varieties are actually natives to the desert, growing wild in the rocky canyons of western Arizona, eastern California, and northern Mexico.

The thousand or so members of the palm- tree family are mostly tropical or subtropical in origin, however, and only a few of them will survive the rigors of the harsh desert environment.

Although some palms cannot tolerate the dryness of the area, it is largely the cold desert nights of Arizona's winter months that limit their use. Several types are extremely hardly under these conditions, however, and are often used in landscaping, not only by individuals, but by municipalities and businesses as well.

The palm tree seems to fit in well with almost any type of landscaping theme, whether it be a simulated tropical setting of banana trees, philodendrons, and dracaenas, or a natural desert yard with yuccas, agaves, and cacti.

Quite often a pair of palm trees may be the only plants in a small front yard and look equally at home in green, grassy lawn or one consisting entirely of gravel.

Nurseries stock large quantities of the most popular types of palm trees, many of which are quite low in price.

Most homeowners buy those small enough to take home in the back of the family station wagon, but specimens 20 to 30 feet or taller can be bought, too. The cost of installation for one of the large varieties -- necessarily done by a landscape contractor with special equipment -- will run several hundred dollars, the exact cost depending upon the type of the palm and the accessibility of the area where it is to be planted.

The only preparation necessary to plant a palm tree is to dig a hole somewhat larger than the root ball.

Where the soil is very hard, especially where there is caliche, it is best to dig a hole that is at least 5 feet wide and 6 feet deep. This affords proper drainage and also gives room for the roots to expand. Little or no soil mix or fertilizer is needed for most types; all one has to do is keep them watered.

Not only are palm trees easy to plant, but they are evergreen, do not shed leaves or bark, and have smaller water requirements than many shade trees.

Maintenance on small specimens is very slight, usually being limited to a once-a-year trimming of the dead fronds. Some people prefer the more natural effect of letting the dry fronds remain on the tree, accumulating into an attractive skirt that hangs beneath the green and growing leaves.

There are certain problems in this practice, however. The dead fronds provide a good shelter where paper wasps build their nests and raise their young , while black widow spiders spin their webs among them. Also, particularly in the larger cities, these dry fronds often become the target for vandals, who set them ablaze, often destroying the entire tree.

When one is choosing a palm tree for his home, he should keep in mind that some varieties get quite large. The small tree that looks so great in a corner of the front yard now may, within 10 to 20 years, completely overshadow the house and yard, overhang the street, and become entangled in power lines.

Unless one has a very large lot, the smaller varieties are usually recommended.

For the homeowner with large palm trees, maintenance becomes a problem as well. Core peeling and frond trimming are difficult tasks on a tree that may be 40 to 60 feet high and requires special equipment to handle. There are companies that specialize in palm- tree trimming, of course, but the service can be quite expensive, particularly if one owns very many large trees.

Another problem to consider with tall palm trees is the fact that they are quite susceptible to lightning damage.

Large palms are often used as decorative plantings by businesses, parks, universities, and city landscaping departments. They are sometimes grown in clumps, with several types together, or they may be planted singly as an accent or background plant with other types of vegetation.

Rows of the very tall varieties are often used as skyline plantings.

In southern Arizona one may choose among at least a dozen varieties of palm trees, although there are only two basic leaf forms. There are those trees that have long, feather-shaped fronds with pinnate leaves.

The most common of these are the date palms. Originating in the Canary Islands and the Middle East, they do exceedingly well in the desert and grow to a height of more than 60 feet and at times cover an area almost that wide with their long, drooping fronds.

When small, date palms make a very attractive accent plant for the yard or patio, but their eventual size should be kept in mind.

Date palms are often seen growing in huge groves, particularly in the Phoenix and Yuma areas, where they are raised commercially.

Although an individual tree will produce huge clusters of delicious dates, the home- owner must be prepared to cover the clusters with nets or bags to protect them from the many species of birds which consider them to be just as delectable as do humans.

Another tree with long, feathery fronds is the queen palm, a very attractive plant with arching stalks and bright-green, glossy leaves at the end of a straight, slender trunk.The trunk needs to be shaved periodically or peeled to keep its smooth appearance. Also, this tree is somewhat more subject to frost and wind damage than many of the others. It reaches a height of 50 feet.

A smaller tree of this same form is the windmill palm, a native of China. Although it can grow to a height of 30 feet, it does so very slowly; therefore it is often used as a container plant, indoors or out.The trunk of this species is single and covered with hairy fibers.

There are also palm trees with fan-shaped, or palmate, leaves. Among them are the California fan palm and the Mexican fan palm, both of which are often best known by their scientific name, Washingtonia.m Their spreading, fan-shaped leaves give a tropical effect, but they are both natives to the desert and are extremely hardy.

Growing to a height of 60 feet or more, they are among the largest of palms in the area, but very young specimens are extremely common in yards and patios. They are among the most important plants in city planning, urban renewal, and parks and recreation areas in southern Arizona, and huge quantities of them are grown in nursery lots for this purpose.

The Washington fan palm, as it is often called, has wide-spreading branches which, until the tree is quite tall, grow low to the ground.

A common mistake in this area is to plant a very small specimen near a walkway, only to have it spread outward in just a few years, completely blocking off access to the house.

The Mexican blue palm is a native to Sonora and Baja California and to the islands of the Gulf of California. There it is found in hot, boulder-strewn canyons. It grows to a height of 40 feet and is extremely tolerant to heat, drought, and wind.

It has large, silvery blue leaves that are barbed along the stems. The Mexican blue palm needs little grooming and is very popular, particularly for use in backyards, patios, and around pools.

Another fan-shaped type is the Mediterranean fan palm, which often grows with several trunks and only to a height of 20 feet. It is an ideal container plant, as is the pindo palm, a very small, feather-form tree seldom reaching more than 10 feet.

Given a choice of the above varieties, the desert gardener can, with a minimum of expense and labor, add the attractive gracefulness and luxurious green foliage of swaying palm fronds to his patio and yard.

With a few holes dug and a quick trip to the local nurser y, he can create an instant oasis.