Few fruits are as strongly identified with the Southern California lifestyle as the avocado. We grow up with guacamole--yet few of us harvest the avocado ourselves, owing to the size of the huge, sprawling trees, some of which reach a height of 35 feet or more and spread almost as far.
However, there is good news for avocado lovers who have an average or even small yard. According to Gray Martin, an avocado researcher at the University of California, Riverside, there is an avocado tree available that requires little more than a third of the space of the typical avocado tree and produces twice as much fruit. The tree is a grandchild of the famed Hass avocado--the favored commercial variety and one of the very best eating avocados.
The tree is the Gwen, and while it is not a new variety, it is not widely known and has only recently been available at local nurseries.
Martin said the Gwen was developed about 25 years ago by Dr. Bob Bergh of UC-Riverside.
Martin says the Gwen avocado tree naturally grows about 15 feet in height, but can be kept even smaller because the tree lends itself easily to pruning as it has small limbs. The harvest period for Gwen begins in April and extends through September.
Although the flavor is similar (Martin considers it better) to the Hass, the fruit does not turn black when it ripens. The fruit has the same thick, pebbly skin as the Hass but has a little rounder shape. The fruit is set in huge numbers uniformly throughout the tree.
For those who have a large yard, Martin discussed other avocado varieties that are grown in the Southland. Here is his rundown:
--Hass: This tree produces pebbly, dark-skinned fruit of medium size. The flesh is rich and buttery with superb flavor. Hass ripens from April through October. The tree grows quite large. Most of California's avocado production comes from this variety.
--Fuerte: A large, spreading tree that produces medium to large pear-shaped fruit with fairly smooth, green skin. The flesh is creamy and the flavor is very good. Fuerte is harvested from October through April.
--Pinkerton: A medium-sized tree. Fruit resembles a Hass, but with green skin. Excellent flavor and a small seed-to-flesh ratio. The tree is quite productive and the fruit generally ripens from January through April.
--Zutano: One of the most productive varieties, it produces medium-sized fruit of average quality. Zutano is a good choice for cooler areas. Large, vigorous tree. Produces from October to January.
--Reed: A slender, tall tree that bears very large, round fruit of excellent flavor and texture. Fruit ripens from mid to late summer through fall. Not good in cooler zones.
--Mexicola: A smaller than average avocado tree that produces small, black-skinned fruit of good flavor. Mexicola is also a good choice for cooler areas as it tolerates lower temperatures than most varieties. Harvest period runs from late summer through October.
--Bacon: Attractive medium, upright tree that produces medium-sized green fruit from November to March. Fairly good fruit quality.
If you want to grow an avocado tree in your yard, Martin says you will need a sunny planting site and well-draining soil. If allowed to stand in water, the tree will not survive. The soil should be kept moist, but never soggy. Older, mixture trees will get along on less frequent watering than young trees, however, every fourth or fifth irrigation should be a deep one to wash away accumulated salt in the soil.
Among other cultural practices, Martin notes that avocado trees have feeder roots that are extremely close to the soil, and the trees benefit greatly from a mulch around the root zone.
So instead of raking up the leaves beneath the tree, allow them to accumulate, rot and provide the tree with a natural mulch that will keep the root zone cool and protected. Also, don't prune the lower skirt branches on the tree as they provide cooling shade, sunburn protection, and wind protection for the accumulated mulch build up.
In most Southern California soils the trees will thrive with little fertilizer. A light application of an avocado fertilizer containing chelated iron on a yearly basis in the spring will suffice. Always water thoroughly after fertilizing.
The avocado tree requires very little pruning, other than for shape and size.
Martin says avocados should be harvested when they are full-sized and mature, but still hard. Green-skinned varieties like the Gwen are usually picked when the fruit loses its shine; the dark-skinned varieties when deeply colored.
In harvesting avocados, don't pull them from the tree by the stem, but use clippers and cut them off as close to the fruit as possible, Martin advises. Never leave the harvested fruit out in the sun for any period of time as it sunburns easily. Allow the fruit to ripen at room temperature; this usually takes about a week.
If you have too much fruit, store some in the refrigerator while the fruit is still hard; then remove in a week or so and allow it to ripen at room temperature.
\o7 Sidnam has written garden columns and features for The Times since 1975. \f7