This variety, found by Carl Schmidt as a dooryard seedling tree in Atlixco, Mexico in 1911, has long been the standard of the California avocado industry and is referred to as a fall and winter variety. The tree is large and spreading and intermediate in its cold resistance to about 27°F. The fruit is green in color, pear-shaped, 8 to 14 ounces in size, and of very high quality. It performs best away from the coastal influence but not in the hot interior growing areas. Although good crops are produced regularly in a few areas, yield generally tends to be erratic in most of the areas where it is planted. Individual trees in a grove may produce good crops while many may produce little or nothing. The suggested tree spacing is 20’ x 20’ to be thinned as they crowd.
Fruit is said to be “set” when the flower has been pollinated, most frequently by bees. For pollination to be effective, nighttime temperatures need to be 50°F or above and daily average temperatures 70°F. In addition, conditions should be favorable for good bee activity to transfer the pollen from one flower to another. The Fuerte, our problem variety, is known to set better crops when interplanted with varieties such as Covocado, Jalna, Topa Topa, and Zutano, which have “A” type flowers that cross pollinate the “B” type Fuerte flowers. At present, the Zutano variety is the only one recommended for commercial use.
Because the Fuerte has a long period of bloom that may extend from Labor Day to the Fourth of July, there may be more than one set of fruit on the trees at the same time. If warm periods occur during this time, some fruits may set and produce “off bloom” fruit that matures in early fall and brings better prices. Off bloom fruits generally have a flattened bottom and are squatty in appearance. Differentiated from the off bloom fruits, the first fruits of the regular crop set are known as “early bloom.” These mature earlier than the main portion of the crop, are of the normal Fuerte size and shape, and may be harvested at the same time or slightly later than the off bloom fruits.
Most noticeable on newly set match head and pea sized Fuerte fruits are the red stems, indicating they are likely to reach maturity. This is a sight that growers just love to see. When temperatures are borderline for good fruit set, “cukes” may be formed. These small, finger-sized, unpollinated, seedless fruits are marketed as “Cocktail avocados” and bring a good price.
The original tree, a chance seedling, was grown and selected by Rudolph G. Hass in the early 1920s at 426 West Street at La Habra Heights. It is thought that the old variety is probably the genetic source of the Hass. Mr. Hass and Mr. H.H. Brokaw, father of the present owner of Brokaw Nursery, saw great promise in this seedling and it was registered with the California Avocado Society in 1932. Later, Mr. Hass applied for a plant patent on his tree and was issued Plant Patent Number 139, on 27 August 1935. A commemorative plaque, supplied by the California Avocado Society, has been placed next to the mother tree.
This variety is a vigorous, moderately spreading tree that produces a high quality fruit, mostly dark-skinned at maturity, weighing 6 to 14 ounces. It is ovoid to pear-shaped with a tough, pebbly skin; ships well; has a good shelf life; and since the early 1970s has enjoyed wide consumer acceptance. The commercial season is from May to October, although there is usually some fruit available year-round. Mature trees tend to have alternate bearing habits, are tender to frost below 30°F, and should be planted only in locations that are nearly frost-free. The Hass variety has replaced the Fuerte as the standard of the industry. As a spring and summer fruit, it complements the Fuerte, a fall and winter fruit. Suggested tree spacing is 15’ x 20’ to provide for early heavy crops and for later tree thinning to maintain production.
Growers in the Ventura-Santa Barbara area have noted that the set on Hass trees is improved by being in close proximity to Bacon variety trees. Hass has an “A”-type flower that is complemented by the “B” type of the Bacon. The percentage of improvement has not been determined by any serious investigation.
This variety is believed to have originated in Fallbrook on the old Truitt Ranch on Alvarado Street. Zutano is a vigorous, upright, precocious and cold resistant variety (26°F). It is a regular and heavy producer of green, pear-shaped fruit of medium size (8-14 oz.), but of modest quality, because fruit tends to split on the bottom and neck when over mature. Because of its penchant to set heavily, the tree requires training and propping to support the crop. It bears well over a wide range of climatic conditions and complements the Fuerte variety as a cross-pollinator when used as an interplant in the Fuerte grove. Zutano has a “B” type flower.
The fruiting season is October to January. For marketing purposes Zutano fruit, along with several other green fruits, are referred to as “other greens.” Trees planted at a spacing of 15’ x 15’ with no more than five tree rows between ranch roads work very well. Unlike the thinning problems of Hass and Fuerte varieties, tree topping will be beneficial to reduce picking costs and to enhance production.
In his search for a cold resistant variety that could be grown on his ranch in Buena Park, California, James E. Bacon planted large numbers of seed and fruited the resulting seedlings. One of these showed exceptional hardiness, was named Bacon, and was introduced to the trade in the late 1920s. The tree is upright, hardy to 24°F, and used in the colder avocado producing areas. While the tree and the fruit tolerate cold remarkably well, the fruit stem is its “Achilles heel” and weakened fruit will require prompt harvesting after a cold snap. Because the variety is mostly grown where cold is a threat, the fruit should be marketed before cold becomes a problem. The fruit is dark green, oval in shape, of medium quality, and from 7 to 14 ounces in weight. In the interior growing areas it develops a serious end spot problem that requires prompt harvesting when mature. The season is November to January. When the fruit is marketed, it is classed as “other greens” along with other green-skinned fruit marketed during the fall and winter.
Growers in the Pauma Valley area feel that a planting combination of Bacon and Covocado varieties complement each other, resulting in improved fruit set. The Bacon has a “B” type flower. The two varieties may be set out on a 15’ x 15’ spacing. On steep slopes the ranch roads should be close together, with perhaps only three rows between roads. On more nearly level land the distance between roads may be increased to as many as six rows. Closer roads provide easier access for grove operations and for fruit removal during harvesting.
The late James S. Reed found and observed a chance seedling in his 6-acre grove in Carlsbad, California in 1948. After several years of records, he became so impressed with its virtues that he applied for a patent. Patent number 1967 was granted to him on 16 August 1960 and expired in 1977. It can now be propagated without paying a patent fee. The Reed variety is thought to be a hybrid between the Nabal and Anaheim varieties. It seems to be the result of a “perfect marriage” because it has all of the positive attributes of the parent varieties with none of the negative attributes of either.
Mr. Joe L. (Roy) Shields, who married the widowed Mrs. Reed, has been active in the promotion of this variety that has won a place on the California Avocado Society’s recommended list.
The Reed has an “A”-type flower and the trees may be planted at a spacing of 15’ x 15’. The tree is upright and a heavy and regular producer of fruit. Reed fruit are large, green, nearly round, and weigh from 8 to 12 ounces near the coast and 12 to 18 ounces in the inland areas with a good seed to flesh ratio. This commercial variety is of very fine quality when harvested after Labor Day, though it is harvested July through September and selectively picked to the middle of November. The tree’s frost tolerance is comparable to Hass (30°F), and the fruit has good shipping and shelf life qualities.
There are, and have been, other varieties of good to excellent quality that are suitable as dooryard trees for the home owner and for trial by the commercial grower for experimental purposes. Three of these new varieties have been named and introduced to the trade as potential commercial varieties and are now in the process of being evaluated.
Jim is anew variety developed by Jim Bacon in the Buena Park area from a Bacon parent. The tree is vigorous, semi-upright, and appears as hardy to frost as the Bacon which tolerates temperatures of 20°-24°F. It is a precocious bearer, produces good crops regularly, and propagates easily from either buds or grafts.
The fruit is green, pear-shaped to long-necked, has a medium-sized seed that is tight in the fruit and a medium thick skin, averages 8 to 10 ounces, and ships well. The fruit tests 14% oil content in early November. Jim has been planted on a limited scale but since the fruit has a long neck, it creates a problem for the packer at times, as long necks are less than compatible with the sizing and packing equipment. This good quality fall fruit is marketed as “other greens” and commands about the same price per pound as Bacon and Zutano. Its flower type is not yet determined.
This new variety originated in the grove of John Pinkerton located in Saticoy, Ventura County. Mr. Pinkerton died in 1979. His son, Allan, has been quoted as saying that it appears that sloppy farm management produced the seedling. One might suspect that nearly all varieties have come to us by loose farm operations. It is believed that the tree is a cross between the Hass and Rincon varieties with cold tolerance about equal to the Hass.
The tree was patented by Mr. Pinkerton and assigned Patent Number 3712 on 29 April 1975. Exclusive propagating rights have been given to the Brokaw Nursery in Saticoy and trees are sold with a patent charge of $1.00 per tree.
The tree is of medium size, but more spreading than Hass. It is clearly from the Guatemalan race with an “A”-type flower. Typically it has two sets of fruit in Ventura County that mature in October and November with the bulk of the crop coming off in the winter and very early spring. Marketing season in general is November to March. The tree is a very heavy bearer.
Warren Currier III, a keen observer, has reported in his “The Agricado Market Weekly” newsletter the following interesting points:
a. The tree seems to have much greater limb strength and tolerates winds better than most other varieties;
b. It is much less alternate bearing in its production habits than Hass and is a precocious bearer;
c. It has a long shelf life and will hold in cold storage for two weeks, which may make it a superior export variety.
Some have referred to the fruit as the “Ventura Fuerte’’ or the “Winter Hass.” The fruit is green with a medium-thick leathery skin that is pebbled much the same as the parent Hass and weighs from 8 to 14 ounces. The high quality flesh has a high oil content and is smooth in texture. It ships well and has a good shelf life. It has at least one drawback, because some years the fruit has a “neckyness” (a long neck), which seems to be a peculiarity of juvenile trees, that does not mix well with the packer’s equipment. The weather may also be a factor that is involved in the production of these long-necked fruits.
This would seem to be a variety tailor-made for San Diego County growers, who have land warm enough to grow Hass. Creating a mix of Hass, Reed, and Pinkerton would permit them to harvest fruit year-round from varieties with a similar frost tolerance. Due to its early season, precocity, heavy production, and high quality, the Pinkerton deserves serious consideration as a commercial variety in new avocado plantings.
Around 1960, Stephen R. Nemcik of Buena Park, California planted a Zutano seed in his backyard. Since it came into bearing it has carried a heavy crop of fruit every year. During the fall of 1971 this tree was brought to the attention of James E. (Jim) Bacon, a long-time avocado grower and developer of the Bacon and more recently the Jim avocado varieties. He found the fruit to have early maturity and excellent size and appearance. After checking the fruit for quality and even ripening he reached the conclusion that here was “the most promising early fall variety yet.” Because of this, Mr. Nemcik applied for and was awarded Plant Patent 3,703 on 15 April 1975 for this tree under the name Santana.
The tree is an upright grower, resembling its parent, the Zutano variety. It is precocious in bearing with first year grafts often setting fruit and setting heavy crops in the second year and thereafter. The tree appears to be about as hardy as the Zutano.
The fruit resembles Zutano in appearance but is somewhat larger and has no end spotting, while the seed is average in size and the skin thicker than most fall varieties. Maturity dates are earlier than both the Bacon and Zutano varieties in Buena Park, with fruit ready to pick by the end of September. Quality is good at earliest maturity and progresses to very good. It differs from other early varieties because it hangs well on the tree as late as March.
During the many years it took to bring the avocado to its present stage of commercial development, many varieties were named both from the United States and from foreign sources. A record of these may be found in the back issues of the California Avocado Society Yearbooks. Suffice to say, the great majority of these littleknown varieties have been systematically eliminated since the industry cannot afford to handle all of these “cats and dogs.” The result has been the concentration of a few varieties as the backbone of the industry, and these have been described in more detail on previous pages.
Many trees of these old varieties are still in existence where old groves have been subdivided and some of the avocados left as ornamentals in yards. Some of the owners of the older, smaller groves have never top-worked these old varieties to commercially acceptable ones and these continue to produce small quantities of fruit that is eaten by the owners, sold locally, or given to friends. These old trees must have some redeeming features or their owners would not keep them merely for their historical value, though this may also be a factor in their survival. In the opinion of their owners, these old varieties produce fruit of much higher quality than the commercial varieties on the market today, which are often picked when the price is right but without regard for maturity and subsequent poor quality. The homeowner can give more individual attention to his trees and pick them when the fruit quality is highest and thus afford to keep a few trees that will give him satisfaction rather than remuneration. One long-time grower, now deceased, was once asked “Why do you grow that watery, poor-tasting Anaheim variety?” He answered, “Oh, I don’t grow Anaheims to eat, I grow Anaheims to sell.” For eating he grew Benik, Nabal, and Queen, three high-quality varieties that are of too large a size for commercial use.
Some folks will eat an avocado, stick three toothpicks in the seed and grow a tree in a glass of water. When it grows into a small tree, they wonder what to do with it. The answer is to plant it -- providing, of course, that they live in a climate where the avocado will grow. It will make a nice ornamental evergreen tree that in time will bear fruit. Half the fun of growing such a tree is the suspense of waiting to see just what kind of a fruit it will have. And, if anyone should attempt to disparage the growing of a seedling tree for fruit, let it be said that as of this writing, every one of our accepted varieties originated as a chance seedling in someone’s grove or back yard. Because most of the seeds that consumers plant come from very good fruit, chances are very good that the seedling will produce fruit of at least acceptable quality and perhaps even of exceptional quality, size, and quantity. Such a dooryard tree might even combine these characteristics to the extent of becoming a new and better variety for commercial use. The best avocado variety has yet to be developed and named.
The California Rare Fruit Growers is a dedicated group of enthusiasts and hobby growers that are always looking for just such an exceptional tree, be it an avocado or any other kind that produces a better fruit than what we now have. Toward this end, two avocado varieties have been named and registered with the California Rare Fruit Growers. The first of these was grown by Orton H. Englehart of Escondido, who introduced it under the name ‘Creamhart’ and registered it on 2 December 1974. It is a pear-shaped green fruit weighing from 10 to 16 ounces with a small seed and flesh of a very fine flavor. The tree is round-headed and produces a good crop every year, ripening from late January to early June. The tree is frost tolerant to 27° F.
The second was registered on 4 July 1977 under the name of ‘Stearns’ and was found in Baldwin Park in the early 1920s by Alex Stearns, who propagated and grew it for many years. The fruit very much resembles the ‘Fuerte’ variety in appearance and was marketed by Stearns as an “early Fuerte,” the quality being as good or better than the Fuerte. Fruits weigh 8 to 14 ounces, have a medium-sized seed, and mature from October to February. Oil tests have shown the fruit to have 10% oil content on 1 September, 15% on 1 October, and 20 to 25% the remainder of the season. The tree is upright spreading -- somewhat similar in shape to the ‘Hass’ variety. Production is good and regular. Stearns is a fall fruit of high quality that could well produce commercial dividends for growers. The tree is frost tolerant to 26° F.
These two varieties, combined with a summer variety such as ‘Reed,’ could make a three-tree dooryard avocado orchard that would provide high-quality fruit year-round for a family, plus some for your friends and neighbors.
In all varieties of avocados there are two periods during the year when a certain percentage of the fruit that has set will drop. This is particularly evident during years when there is a very heavy set of fruit. “June drop” has been identified in other fruiting trees as well as avocados. At this time, many pea-sized fruits will be found on the ground. Later, after the fruit has matured to walnut on up to lemon size, there is another period when a lesser amount of fruit will drop, usually during the month of August. Any estimates of the crop for the following harvest year should be made after the August drop, which is the last drop that can be expected before the fruit matures.
The reasons for these two drops are not well understood. The June drop may be due in some way to improper pollination when the nights were too cold for the pollen to be effective. The August drop is probably due to a self-thinning by the tree, which may have set more fruit than it can comfortably carry. When these dropped fruits are cut open, the seed is black and dead -- hence the fruit will not mature further and is aborted. The Hass variety is particularly subject to fruit drop. In any event, fruit drop is no cause for concern because the tree will still carry a good crop to maturity in spite of the drop.
Figure 17. A ranch road in an avocado grove is littered with fruits from the August fruit drop. Trees will still mature a full crop.
Nursery trees are produced from selected Mexican type seeds such as Topa-Topa, Mexicola, and Ganter that have been heat-treated to kill any root rot fungus that may be present. Since the early 1970s, nurserymen have found that West Indian seeds produce good nursery trees that are much more resistant to salts in the soil than the Mexican rootstocks. Because the West Indian stocks are not cold tolerant, they are used as rootstock for the Guatemalan varieties such as Hass and Reed, which are planted on warmer land.
In the early years of the avocado industry all nursery stock was field grown. A 1/8” slice of the bottom of the seed and about ˝”of the top were cut off to promote growth, the seed coat was removed, and the seed planted 18” apart in rows directly in the ground. A large Dixie cup was placed over the seed, and dirt was packed around it to hold it in place. When the seed started to grow, the top was removed from the cup or the entire cup was removed. After the stem of the tree reached 3/8” to ˝” diameter, the tree was budded to the variety of choice. A “T” shaped cut was made in the trunk and a shield-shaped bud inserted under the bark and securely tied with rubber budding bands or plastic tape. The top few inches of the tree were removed at the time of budding. When the bud had grown to a length of about 3”, it was tied to the upper portion of the tree to keep it growing upright. Later, the balance of the rootstock was removed immediately above the bud. This point is called the bud union.
Budding was done in the early summer and if sufficient growth was made by the bud, the trees were ready for digging in the spring. An 18” balling spade was used to dig around the tree and remove an 8” to 10” diameter tapered ball of dirt containing the roots. This was wrapped in burlap and securely tied with binder twine. At this time, half of each leaf and a few of the smaller limbs were removed to balance the top with the root system that was pruned when the tree was dug up. These trees were delivered to the grower “balled and burlapped” and ready to plant.
In planting these field grown trees, the ball was placed in the hole and the dirt backfilled to cover about 2/3 of the ball.
The twine at the top of the ball was cut and the burlap laid back on the ball and the remainder of the soil placed on top of the burlap. This prevents the soil in the ball from drying out because the burlap acts as a wick to evaporate the moisture from the ball if it is exposed to the atmosphere.
In the evolution of growing nursery stock in the field to the present day practice of growing stock in plastic bags and tubes, a transitional stage was used. In this stage, seed was planted at a depth of some two inches in seed beds about a foot deep, and when the young trees were some 6” to 8” tall they were transplanted to bottomless tar paper containers about 5” in diameter by 16” deep. They were then budded in the containers and sold to the grower when large enough to plant. With container-grown trees, growers have the advantage of not disturbing the root system as with those trees removed from a field. A disadvantage is that the tree may remain in the container too long, if not sold, and the root system becomes pot bound to the point that the tree will not grow well when planted. This may be partially remedied by moving the container to prevent the roots from growing into the ground. If the root ball becomes pot bound a knife may be used to cut through the roots from top to bottom after which lateral roots will be initiated. This is done immediately after the container is removed and just before placing the tree in the planting hole.
During the 1970s there was a tremendous expansion in the acreage planted with avocados, which in turn created an unprecedented demand for nursery-grown stock. Old nursery practices were much too slow, forcing nurserymen to delay filling their orders for as long as three years after they were placed. To accelerate production, they turned to greenhouses with controlled temperatures and humidity. Seeds were planted in small 2” by 8” plastic bags or tubes and when the young trees were about 3/16” in diameter the tops were cut off squarely and split for an l˝”. A small terminal scion some 3” long was trimmed to a wedge shape at the basal end and inserted into the split trunk. It was then tied with a rubber budding band and placed in a greenhouse with high temperatures and humidity, where the stock and scion quickly made a union, and within two weeks the graft commenced to grow. This rapid growth is achieved due to the large food reserves stored in the seed. After the young graft is well established, the tree is hardened off in a cool greenhouse and then transplanted to plastic sleeves 6” by 18” deep and grown outside of the greenhouse until sold to the grower for planting.
Due to the ravages of root rot, the latest development is the grafting of clonally propagated, root rot resistant rootstocks. This is an insurance policy against times when a grove becomes infected with root rot. The University of California Riverside’s Dr. George Zentmyer has found several trees that are highly resistant to root rot, and these are propagated for rootstocks. Because it is almost impossible to root these in the conventional manner, a different method for rooting them has been developed by Mr. Edward F. (Ted) Frolich of UCLA.
This method is known as the etiolation technique. Only avocados with very large seeds are used as seedling rootstocks for etiolation rooting. Seeds are planted in gallon cans and grafted to the clonal scion. When the stem of the graft reaches about Ľ” in diameter, the top is cut off just above a whorl of buds that is generally found within an inch of the graft union. A 4” wide band of black tar paper is formed into an extension of the can and filled with vermiculite. The plant is placed in a dark box with high temperature and humidity and the food reserves in the large seed quickly cause several of the buds to grow up through the four inches of vermiculite. When growth is some 3” or 4” above the vermiculite, the plant is removed into the light, where the upper portion will quickly assume a green color to provide food for the plant. The tarpaper collar is then removed, the branches severed from the plant, and the branches are then placed in flats where the cuttings are rooted in the conventional manner. Because the basal portion of the cutting has no chlorophyll, it performs as an underground stem and soon sends out adventitious roots. The rooted cuttings are transferred to containers and grafted in the usual manner to provide nursery trees with a known degree of root rot resistance. Duke 7, Duke 6, Huntalas, G-6, and G-22 are recommended by UCR for propagation.
The avocado nursery industry operates under two concepts that have the intent of assuring the grower that he is buying quality trees. These are registration and certification of nursery stock, and these concepts are controlled by state regulations developed by the avocado industry itself.
Registered nursery trees are those produced from seeds and scions known to be free of the sun blotch viroid. Registration may become less important following the discovery that sun blotch can be transmitted on pruning tools and by insects pollinating the flowers.
Certified trees are those produced under sanitary growing conditions. Avocado seeds are immersed in a vat of hot water at a temperature of 120°F for a period of 30 minutes to kill the root rot fungus. If the seeds are not planted immediately after the heat treatment, a fungicide is applied to them and they are held in cold storage to prevent growth until they are ready to be planted. In order to insure that trees are free of root rot, procedures include the following: the potting soil is sterilized, the trees are grown on concrete to avoid contact with the ground, and personnel are required to step in a fumigant before entering the growing area. Trees that are certified as free of the root rot fungus sell for about twice as much as regular nursery stock.