Why do gardeners go to all the trouble of growing their own fruit trees?

I think the answer is flavor.

Many fruit varieties are not available in grocery stores or even farmers markets. A backyard orchard is the only way to get these.

With a backyard orchard, gardeners also can control when the fruit is picked. This can make all the difference in flavor. We should discuss the difference between mature and ripe fruit. Ripe fruit are ones that have developed their full flavor and sweetness and have the right amount of softness. Mature fruit are physiologically mature but not necessarily ripe and ready to eat.

Some tree fruit ripen best on the tree, others can be picked at the mature stage and will ripen off the tree. Commercially harvested fruit is often harvested when fully mature but still firm to make shipping and packing easier. Home gardeners have the luxury of picking fruit when fully mature and ripe, allowing fruit to develop full color, flavor and sweetness. Of course, fully ripe fruit bruise much more easily and don't store as long.

So what fruit will ripen off the tree if picked fully mature? Apricots, peaches and nectarines. There is a definite color change from green immature fruit to a yellow ground color. All three are usually mature when the fruit can be easily separated from the tree with a slight twist. But for the fullest flavor, they ripen best if left on the tree.

Plums also will ripen off the tree, but the best flavor comes when they're ripened on the tree and allowed to develop sweet and soft flesh. If you want to pick plums when mature and still firm, wait for the skin color to change from green to the appropriate color for the type (red, purple or yellow) and there should be a slight softening of the flesh at the tip end.

Cherries don't ripen much off the tree and should be picked only when their full flavor and sweetness have fully developed, but while still firm.

Apples are harvested at the right firmness and sweetness for the variety. Commercial growers use special equipment to determine sugar content and hardness of the flesh, but home gardeners can figure this out by simply tasting the fruit. If you pucker up or the flesh has an astringent flavor, they're not ready yet. Apples should be harvested when fully mature and sweet but still firm. This is especially important if you plan to store them for a while. Lift or roll and twist the fruit stem away from the spur. If mature, it should separate fairly easily with the stem attached.

Pears are tricky. They're best harvested when mature but before they're ripe. If allowed to ripen on the tree, they'll have gritty flesh and the cores will have a tendency to break down and become mushy when stored. Winter pears, such as Bosc, Comice and Anjou, ripen late in the season and require cold storage after picking. Fall pears such as Bartlett, Clapp Favorite and Orcas ripen earlier and don't need cold storage.

When mature, fall and winter pears will be green, just starting to turn yellow-green. The stems will separate easily from the spur when the fruit is lifted and twisted.

The seeds inside should be brown. Also, the flesh will yield a "smidge" to pressure instead of feeling rock hard. (I told you it was tricky!) Winter pears are stored for three to four weeks in cool conditions (33 to 40 degrees) before they're allowed to ripen at room temperature.

Asian pears should be allowed to ripen on the tree, just like apples. Their skin color will start to turn from green to yellowish. Asian pears have the best flavor when eaten fresh -- not stored.

* Marianne C. Ophardt is a horticulturist for the Washington State University Cooperative Extension Office in Benton County.