Oranges: Trees With Solid Southland Heritage : Fruit: Even if you only have limited yard space, a semi-dwarf navel and a Valencia will provide harvest almost year-round.

Much of Southern California has an ideal climate for growing oranges. Indeed, your home may be located where an orange grove once thrived. As some of you may remember, in the not-so-distant past much of the Southland was covered with lush citrus groves, and oranges were an important factor in the area’s economy.

Sadly, there are few citrus groves left in the Southland. However, if you have a medium-sized or even a small yard, you can take advantage of this prime citrus climate and grow your own orange trees.

You only need two trees, a navel and a Valencia, to have an almost year-round supply of fresh oranges. The navel orange ripens from December through May, and when it’s harvest period is over, the harvest of the Valencia orange commences and lasts through October.

Now, with semi-dwarf orange trees so commonly available, you can fit two trees into even smaller yards. The semi-dwarf orange trees grow only to a height of 10 to 12 feet and spread to about 10 feet.

If this isn’t small enough for you, control the growth by regular pruning. There are true dwarf orange trees which grow to only 6 to 8 feet, but they are very difficult to locate and quite slow-growing. Most orange trees labeled “dwarf” are actually semi-dwarf trees.

Both navel and Valencia orange trees are available at almost all local nurseries in both semi-dwarf and standard sizes. The standard trees will reach a height of 20 feet or more and spread 15 feet or greater.

The navel orange is one of California’s precious resources; it’s a superb dessert orange that’s not grown commercially anywhere else in the United States. Large and colored a beautiful deep hue, it has a rich flavor, is seedless and easily peeled and broken into segments.

The navel orange was brought to California in 1873. Its arrival in Riverside heralded the birth of the commercial citrus industry in California.

The trees yield a bountiful crop of fresh fruit in a small area. What’s more, they are highly ornamental--glossy, evergreen foliage spotted with beautiful orange fruit and white, delightfully scented blossoms.

There are several varieties to choose from. The oldest--the Riverside original--is the Washington navel. Commercial growers consider it not only the choicest for eating but also the best-producing variety available. Its fruit-bearing period begins in mid-December and continues through May; peak sweetness occurs after mid-January.

The Trovita does well in two areas where the Washington does not: in the desert and near the coast, with a harvest starting considerably later than Washington.

Robertson is a variety that ripens several weeks earlier than Washington and produces at an earlier age, but the quality of the fruit isn’t the equal of Washington.

The Valencia orange has thrived in many Southern California areas since the turn of the century. It is a most versatile orange that is great for eating fresh and unsurpassed for juice. Although Valencias start ripening in spring, the fruit will hold on the tree until October without loss of quality.

When Valencias aren’t picked when first ripe, they tend to do what growers term regreen. That is the rind tends to change back from an orange color to an orangish-green color. This does not affect the fruit and the inside color remains orange. Indeed, the later-picked Valencias that have regreened tend to be sweeter than the ones picked earlier.

Although Valencias are known primarily as juice oranges, if allowed to ripen sufficiently, their flavor is just about as good as a navel orange. They are, of course, much more difficult to peel and section than navel oranges.

Purchase only healthy, vigorous-looking transplants. Avoid trees with long trunks and branches concentrated at the top. The tree should have good skirt branches near the soil line. If the transplant has any fruit on it, pick it off so the tree’s energies will be devoted to foliage production.

Consult your nursery personnel for specific transplanting instructions, but always plant in a sunny area and make sure the grafting union is at least 3 inches above the soil line.

When planting, dig a hole twice as wide as the root ball, but only as deep as the tree was originally grown. Plant the tree and refill the hole with the soil you originally removed. Fertilizer tablets should be added to the soil at the time of transplanting. Water thoroughly after transplanting.

Irrigate the new tree twice a week for four weeks, then water it on a weekly basis. Established trees should be fertilized in March and again in July or August with a general purpose citrus food. Do not fertilize in late fall; this promotes new tender foliage growth that would be subject to frost damage during the winter.

Orange trees are available in cans year-round. If planting a new tree during the winter, if there is a chance of freezing temperatures, put a few wooden stakes about the tree and cover this frame with a drop cloth at night; remove the cloth first thing in the morning.

If planting a new orange tree during the heat of summer, it is wise to paint the trunk with a white latex paint or wrap it with trunk band (available at most nurseries) to prevent sunburn damage.