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Tree laden with avocados
a basket of avocados

His seedling grew vigorously, but he failed at least twice in trying to establish a new graft. Hass considered cutting down the tree, but his children loudly protested, liking the taste of the bumpy, odd fruit the tree produced.


In 1935, Hass obtained the very first U.S. patent on a tree and gave his cultivar the family name. He contracted with a local nurseryman to grow and distribute the trees in a deal whereby Hass would collect 25 percent of the net proceeds from sales.  Unfortunately for Hass, commercial growers simply bought a single plant and used it to graft entire orchards.


Hass only made $5,000 from his discovery, yet the Hass cultivar has become the world's most dominant commercial avocado variety, currently accounting for more than a billion dollars in annual sales in the U.S. market alone.



Three varieties of avocados

But I'm addicted. I could eat three or four a day. That could be a nearly $3,000 a year habit. What to do? Figure out how to grow the darned things myself.


Most people are introduced to avocados in the form of guacamole, often at a Super Bowl party.  Peak avocado season hits right around Super Bowl season. This year, it is expected that 50 million pounds of avocados will be consumed during the Feb. 7 game. That's enough to cover the entire field in guacamole 5 feet deep.


The avocado is a broad-leaved evergreen tree native from Mexico to South America and into the Caribbean. Under ideal conditions, avocado trees can reach 80 feet tall. And it is not uncommon to see trees that are 50 feet tall thriving on benign neglect in the older neighborhoods ringing the San Francisco Bay.







AvocadosHome-growing the fruit keeps a supply nearby

By Gary Gragg

Bay Area News Group correspondent

Posted: 01/29/2010 02:00:00 PM PST


HOLY Guacamole! That's what I say every time I walk into the produce aisle and see how much a single avocado costs — sometimes as much as $2 each.



















The fruit has been highly regarded in Central and South America for more than 2,500 years — seeds have been found alongside buried mummies in Peru dating back to the 8th century B.C. Comparatively speaking, the avocado is a relatively new introduction to California, having been commercially cultivated here for only about 100 years.


The single seed is usually oblong, but it is sometimes nearly round. The avocado is green or black skinned, and it can be as small as a walnut or as large as a cantaloupe.


Why the enormous range of fruit types? Genetic variability. Each seed produced by an avocado tree has its own unique genetic code and thereby has the ability to vary from its parents, or parent — avocados are self-fertile.


Like most plants man finds useful, avocados exhibiting desirable traits have been isolated and replicated via asexual reproduction for hundreds, if not thousands, of years. This is accomplished by grafting the desired variety onto a seedling rootstock or even onto a mature tree.


This process has given rise to more than 500 named varieties, one of which has dominated: the Hass.


Finding Hass

In 1926, a humble postman earning 25 cents an hour hit the genetic variability jackpot when he purchased an avocado seed from a local nurseryman. Rudolph Hass from La Habra Heights planted his seed, intending to grow a rootstalk upon which he would graft an existing common cultivar.




















California dominates the U.S. avocado market, producing nearly 95 percent of the nation's crop. Commercial California groves stretch from San Luis Obispo to San Diego County, although limited commercial growing occurs as far north as Monterey County.


As a result of the North American Free Trade Agreement, avocados from as far away as Mexico, Peru and Chile have begun to enter the U.S. market.


To me, this is absurd. Why should a fruit be shipped from the other side of the world to your local grocery, at an enormous environmental toll, when you can grow it yourself just outside your door?


Grow your own

Cultivar selection is of paramount importance. There are three types of avocados: Mexican, Guatemalan and West Indian.


Generally, Mexican varieties are hardy into temperatures in the low 20s and Guatemalan to the mid 20s, but East Indian get fussy in the low 30s, relegating them to semitropical Florida, Hawaii and the most frost-free locations of Southern California.


In Northern California, try using the most cold-hardy and toughest Mexican cultivars, such as California's first commercial type, Fuerte, the low-fat content Bacon, the early ripening Zutano, or the hardiest of all, Mexicola Grande, which has a smooth, dark purple skin and buttery flesh.

And if you are a bit more adventurous, risk tolerant, have a particularly frost-free location or all of the above, try one or more of the Guatemalan varieties, such as the nearly ever-bearing Hass, the Hass-like Gwen, the easy peeling Pinkerton or the summer ripening cannon ball-sized Reed.

Most exciting of all is a new Mexican type variety named "Sir-Prize" that was derived from a Hass seedling. It produces a fruit very similar to Hass except larger. But it is much more cold-hardy than its tender grandparent.


If you would like more than one variety but are short on space, simply plant two or three in the same hole and allow them to grow into a multi-trunk, multi-variety single tree.


And if you only have room for a large pot on a deck or balcony, choose the dwarf Littlecado, also known as "Wurtz."


Site Selection

In Northern California, the ideal avocado-growing location is just beyond the fog belt, on a south-facing slope at least 200 feet above the valley floor, 250 feet to 1,200 feet above sea level.

Being just beyond the fog belt allows for increased heat without being so far inland that the trees become scorched and stressed from the hot summer sun. Planting on slopes allows for excellent drainage to prevent root rot and increased frost protection because dense cold air sinks and accumulates on valley floors, bypassing plantings on higher slopes.


If the slope faces south, the trees will enjoy much more winter sun and warmth because of the low angle of the winter sun. That said, avocados also can be successfully grown outside these "ideal" site conditions.


Tree planting

Avocado plants are commonly available in 5- and 15-gallon container sizes. Select a tree that appears vigorous and healthy. Dig a hole twice the width and slightly deeper than the container and plant the tree an inch or two higher than the prevailing grade because the plant will surely settle over time.


Backfill the hole with equal parts native soil and well-aged compost, mixed thoroughly. Use the excess soil dug from the hole to create a water basin around the plant to assist in irrigation. Tamp the soil and water deeply to relieve any air pockets.


To prevent damage to the young plant from frost, wind, sun and animals, surround the tree with a mesh cage held in place by rebar stakes. Drape burlap or shade cloth over the cage for the first few years or until it outgrows the apparatus. If gophers are active nearby, cage the root ball using half-inch aviary wire netting, taking care to wrap the entire core root ball to the point of the exposed trunk.


During the first several years, water deeply, thoroughly and frequently to encourage maximum root and top growth. The tree will become more drought tolerant with age, but remember that a well-watered tree will be healthier and bear more fruit than a similar drought-stressed-tree. Always supply ample water during fruit set.


Fertile fruit

A common misconception about avocados is that they are not self-fruitful. This is false, but the flowering habit of avocados is unique in that the flowers are perfect, having both male and female organs, but the parts do not function together.


Avocados are divided between type A and type B flowering cycles. Flowers of type A varieties open in the morning as receptive females, then close in the afternoon until the following afternoon when they reopen for pollen shed.


On the other hand, flowers of type B avocados open in the afternoon as receptive females, close overnight and reopen the following morning to shed pollen.


In other words, the girls and the boys on the same tree just aren't getting together at the right moment. To ensure maximum fruit set, plant type A and B avocado varieties in close, or even overlapping, proximity to each other.


And because bees are the prime pollinators of avocados, anything to increase their numbers in and around avocado trees during their flowering period likely will increase fruit set. Try bee-loving plants such as rosemary. Or establish a hive near your trees.


And remember that avocado trees are beautiful, shade-producing evergreens. They should be used as ornamental plantings and not just relegated to the orchard.They incorporate especially well into subtropical, Mediterranean and Spanish themed gardens. Be aware, though, that they can grow large and have significant leaf drop.


But the benefits of fresh guacamole far outweigh any potential downsides to having this wonderful tree around.


This article is dedicated to Rudolph Hass for bringing to the world such a wonderful new variety of avocado.  Thank you Rudolph!



A small boy, Carson "Dumpling" Gragg, holding up an avocado

Carson "Dumpling" Gragg hungrily eying a Hass Avocado

A large Hass avocado tree in front of a house

The original Hass avocado tree in front of Rudolph and Elizabeth Hass' La Habra heights Home, circa 2000.  Every Hass avocado tree in the world emanated from cuttings off this singular plant.  And sadly, this tree went to Heaven not long after this photo was taken.  BUT in our office we have a cross section of this tree forever memorialized in a hunk of glass.

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