Hass Avocado Patent 139: The History of California’s Most Famous Fruit

The Forgotten History of Plant Patent 139

The Hass avocado was patented as U.S. Plant Patent No. 139 on August 27, 1935, by Rudolph Hass, a postman from La Habra, California, who grew the original tree from a chance seedling. Hass avocado trees dominate modern grocery stores, but few consumers realize that this legendary variety began with that one patent, a turning point in commercial fruit cultivation and agricultural intellectual property.

As a patented inventor running our family avocado grove in Escondido, California, discovering that individual plant varieties could receive U.S. patents was a fascinating revelation. Understanding how the Hass avocado became the world standard offers valuable insight for backyard gardeners, commercial growers, and lovers of fresh fruit alike.

How Rudolph Hass Discovered the Mother Tree

The story of Plant Patent 139 begins in 1926, when Rudolph Hass bought Guatemalan avocado seedlings (thought to be of the ‘Lyon’ variety) from the Rideout nursery in Whittier to serve as rootstock for the popular Fuerte. On the nursery’s advice he planted three seedlings to a hole, planning to graft the strongest and pull the other two. One seedling refused to take the Fuerte buds after three attempts. Rather than cutting the stubborn tree down, Hass let it grow, and for a while it was simply ignored.

The tree eventually produced avocados with dark, pebbly skin, and Hass himself thought the fruit was ugly. According to his son Charles, the children kept telling him it tasted great until he tried it. He liked the creamy flesh, the nutty taste, the lack of fiber, the 18% oil content and the long harvest season.

Winning over everyone else took much longer. Shoppers had learned that an avocado was supposed to be green, and acceptance of the black-skinned fruit was slow. Steady promotion by packers and growers gradually changed that: Hass was 15% of the California crop in 1957, overtook Fuerte in 1972 — forty years after its introduction — and by 1990 was 83% of California production, with Fuerte down to 2%.

Read nextWhy Fuerte Lost California to Hass: Alternate Bearing and a Mail Carrier’s Tree

Key Milestones in Hass Avocado History

• 1926: Rudolph Hass plants the original seedling in La Habra, California.
• 1935: U.S. Plant Patent No. 139 is issued on August 27, granting exclusive propagation rights.
• 1952: The patent expires. Hass has earned only about $4,800 from the variety.
• 1957: Hass makes up 15% of the California crop.
• 1972: Hass surpasses Fuerte in total volume marketed from California.
• 2002: The original mother tree in La Habra Heights dies of avocado root rot at the age of 76.

Why Plant Patenting Changed Agriculture

Before the Plant Patent Act of 1930, plant breeders and horticulturists had no legal mechanism to protect newly discovered or created plant cultivars. Plant Patent 139 allowed Rudolph Hass to partner with nursery operator Harold Brokaw to propagate grafted clones of the original mother tree.

Because avocado trees grown from seed do not grow true to type, every authentic Hass avocado tree growing in California and around the world today descends by grafting from budwood traced back to that original La Habra mother tree. Plant a Hass seed and you get a genetically new tree, most likely one with inferior fruit.

How Much Money Did Rudolph Hass Make From His Patent?

Very little. Hass made a deal with Harold H. Brokaw, a Whittier nurseryman, to grow and promote the new variety, but by the time the patent expired in 1952 Rudolph Hass had earned only about $4,800 from it. The fruit that now makes up nearly the entire California crop never made its discoverer rich.

What Happened to the Original Hass Mother Tree?

The mother tree lived on in a suburban yard in La Habra Heights until 2002, when it died of avocado root rot at 76 years old — the same Phytophthora disease that is still the biggest problem in California groves. Hank Brokaw, Harold’s nephew, saved the wood, and the California Avocado Society still uses pieces of it for plaques and special awards.

Is the Hass Avocado Mexican or Guatemalan?

Both, but mostly Guatemalan. Plant scientists describe Hass as roughly 85% Guatemalan and 15% Mexican. The Guatemalan side gives it the thick, pebbly skin and small seed; the Mexican side adds some cold hardiness. Avocado Production in California: A Cultural Handbook for Growers, Book One, notes Hass does best in subtropical climates like California and the Michoacán highlands of Mexico, and does not fruit and grow well in tropical places such as southern Florida or Hawaii.

By the 2011–12 crop year, Hass was 96.9% of California’s avocado volume. Growers have long pointed out its flaws too — it is cold tender, bears heavily one year and lightly the next, and grows into a very large tree — but no other variety has matched its eating quality and long harvest season.

Hass vs. Other Avocado Cultivars

While the Hass variety offers outstanding post-harvest stability and high oil content, California growers cultivate several other notable varieties, each with distinct characteristics:

• Fuerte: Renowned for its smooth green skin, medium oil content, and creamy taste.
• Reed: A large, round summer variety with exceptional flavor and skin that stays green when ripe.
• Lamb Hass: A late-season grandchild of Hass producing larger fruit with high yields and better heat and wind tolerance than Hass.
• Zutano & Bacon: Cold-hardy green-skinned varieties with B-type flowers. Growers keep them near Hass as pollinizers, since Hass is an A-type, and Bacon is probably the most cold-hardy commercial variety.

Sustaining California Family Farms Today

Preserving the rich history of California agriculture is a core priority at Holmes Grown USA. Managing a historic avocado grove in Escondido requires balancing traditional cultivation techniques with modern soil health, irrigation efficiency, and pest control.

By understanding the heritage of our trees, we keep California farming heritage alive while delivering premium, fresh-picked fruit directly from our grove to your kitchen table.

To learn more about our family farm, explore seasonal avocado availability, or order fresh California avocados shipped directly to your door, visit the official Holmes Grown USA website today. For how Hass pushed the old green varieties off store shelves, see Hass vs Fuerte: why stores only sell one.

Every Hass in our grove traces back to that one tree on Rideout Street. Our 4lb Hass box and 6lb Hass box ship free, picked the week they go out; between harvests the waitlist on either page will tell you when picking starts. Until the trees are picking again, the avocado scoop, the Hawaiian shirt and our hats ship year-round.

This is part of our complete guide to the history of California avocados — the early introductions, the varieties that won, and the growers who are left.