If you've got room for a fence, you can grow an `orchard'

IT is, quite literally, an orchard on a fence. The ``cordon'' (single-stem) method of growing fruit can be used in virtually any yard, and by any gardener. It works very well with apples and pears; a somewhat modified version, ``espalier,'' accommodates the stone fruits such as peaches and plums.

For their size, cordon trees are highly productive, each mature tree yielding from 20 to 30 fruit a year. Along a 10-foot fence, for example, a homeowner could grow 4 or 5 different apple varieties (early, midseason, and late) providing a yield of manageable, family-sized harvests from midsummer through late fall. Trees can be planted from 18 to 30 inches apart. They have little depth to speak of because only those branches to the left and right of the stem are allowed to grow.

Trees can be cordoned vertically, but one horticulturalist, Steven Frowine, prefers growing them at a 45-degree angle. Mr. Frowine used that technique for a ``fence orchard'' he grew at the St. Louis Botanical Garden. He ticks off the advantages of the angled cordon:

The fruit is exposed to a a large amount of sunlight, ensuring high quality and maximum sweetness.

Because fruit and leaves are exposed to so much light and air movement, there is little disease.

Fruit inspection is simple and any spraying that might be necessary is easily accomplished without hitting non-target areas.

All fruit is within arm's reach. No ladders needed.

A large assortment of apple and pear trees can be grown in the space taken up by one conventional tree to provide a continual harvest over several months.

The system produces a most attractive, functional, living fence.

To start a fruiting fence you will need to erect a trellis to support the trees, which become particularly heavy at fruiting time.