An orchard that you can grow in a small yard

You see it more in Europe where they have been practicing it for centuries. But slowly the art of espaliering is spreading to fruit-loving, space-short home gardeners on this side of the Atlantic as well.

It brings with it one simple message: ''You can have a small yard and a fruit orchard, too.''

Espaliering is a way of pruning and training a tree into an upright, flattened form so that, like ivy, it hugs a wall or, like a grapevine, it runs its fruiting branches along a fence. In other words, the amount of space normally taken up by a tree is dramatically reduced, making it possible for even a small yard to have an orchard of its own.

A vast majority of fruit trees - apples, peaches, plums, and the like - can be trained in this manner along either walls or free-standing fences.

Here's one approach:

* Run horizontal wires of lattice wood across a wall at 18-inch intervals for apples or pears or 24-inch intervals for peaches. In cooler regions the wires can be attached directly to the wall, but where summer temperatures frequently rise above 90 degrees F., fasten the wires so they are at least 6 inches from the wall. This will allow for the air to circulate freely behind the tree branches.

* Plant a bare-root sapling, or whip as it is known in the trade, preferably of dwarf or semi-dwarf stock. Ask your nursery for spur-type apples (trees that bear fruit on small fruiting spurs that develop along the branch) rather than a tip-bearing variety.

* Prune the single stem back to level with the bottom wire and allow three buds to develop. The top bud will grow up and continue as the tree trunk, or central leader as orchardists call it. The lower two buds, one on either side of the trunk, are allowed to grow and are tied loosely to the lowest strand of wire to form lateral branches. All other buds on the main trunk are removed as they form.

* Let the central trunk grow to the second wire and then repeat the process, allowing the top bud to continue as the trunk and two other buds to develop as the second set of lateral branches. Continue this process until the trunk reaches the topmost wire.

At this stage the side branches are allowed to develop but no trunk continues. As a general rule a dwarf tree is allowed to develop three sets of lateral branches and a semi-dwarf, up to five laterals.

* Once the trees have become dormant (late fall or late winter), prune the laterals back by at least one-third of their past season's growth, preferably to a downward pointing bud. This bud continues the lateral growth of the branch the following season while small fruiting branches develop all along the branch. In the early summer top these little side branches back to three sets of leaves to encourage the development of fruiting buds that will flower the following spring.

Remember the old adage: Dig a $5 hole for a $1 tree or, more accurately, a $ 25 hole for a $5 tree? This advice applies as much to an espalier as it does to the free-growing tree. Even a very dwarf tree will bear for at least 10 years, and often a lot longer, so start it out right.

Dig the hole at least twice as wide and somewhat deeper than the root system. Place the top 12 or so inches of soil on one side and the subsoil elsewhere. Mix in with the topsoil as much compost and/or well-rotted manure as you will need to fill the hole when planting. Or you can add milled peat moss that has been enriched with several handfuls of composted cow manure (both obtainable from a garden center).

Now plant the tree as you would a rose by spreading the roots around a mound of the soil mix at the bottom; then fill in with the reamining mix, firming it with a foot when the hole is about three-quarters full. Fill the hole with water and allow it to soak away (twice).

Now add the remaining soil mix, leaving a slight depression around the tree to hold water.

A word of caution: Plant the tree so that the bud union (the swollen section where the stem has been grafted onto the roots) is just above the soil surface.

A few years ago I planted the union below the soil surface, which thus encouraged the stem to send out roots of its own. As a result, the onetime dwarf is now well on its way to becoming a full-sized standard tree that is too large for my small garden.