In 1984, a new avocado variety was patented by the University of California and released to growers. It was called Gwen, and it showed great promise. 

Gwen was estimated to produce approximately double the amount of fruit per acre compared to Hass, the standard variety. More than that, most people thought it tasted as good or better. (See, “Three New Patented Avocados.”)

As if that weren’t enough, Gwen trees were also smaller than Hass, which made the fruit easier to pick, plus they produced more fruit at a younger age, meaning you would get a quicker return on your planting investment. (See, “The New Gwen and Whitsell Avocados.”)

Before I had my own experiences with growing and eating Gwen, I read about these details of the variety in the California Avocado Society Yearbooks, in articles in the Los Angeles Times and elsewhere, and I was attracted.

I was also mystified, because after 1994 Gwen essentially vanished from the written record. Tom Markle, an avocado farmer in Escondido and a former president of the California Avocado Society, wrote in the 1994 Yearbook an article titled, “Gwen Variety Update,” and it was the final word on Gwen that I know of. Markle wrote that he had had “mixed experiences growing the Gwen” but concluded the article by noting that his Gwen trees had at that time their best fruitset ever and he believed “that the Gwen variety can and should survive.”

Markle’s was a mixed message. It seemed that Gwen wasn’t perfect but neither had it shown serious flaws.

Nonetheless, Gwen did not survive, not commercially. Markle’s “Gwen Variety Update” turned out to be the Gwen variety’s obituary.

Why? What happened? I’ve been trying to understand this for the past 15 years, through eating Gwen fruit, growing the trees myself, and asking people who were eating the fruit and growing the trees before me, during Gwen’s commercial appearance and disappearance, about their take on the Gwen story.

I want to understand Gwen for its own sake. I find Gwen one of the best avocados to eat, and in my experience it is a fruitful tree with a long harvest season. So I want to know what went wrong with Gwen, but I also wonder if it has lessons for the future of other avocado varieties.

Three main problems

I’ve picked the brains of farmers, harvesters, handlers, breeders, and eaters. And the one thing I’ve learned is that there is no consensus, no single answer, as to what happened to Gwen. Nevertheless, I’ve noticed that three reasons for Gwen’s rise and fall are mentioned by most.

Green skin

Of the three most common reasons given, Gwen’s skin color tops the list. Always, people mention the green skin. Gwen has green skin, and the green skin is a problem.

In short, it’s because in the 1980s, when Gwen arrived, Hass had just become the dominant avocado variety and it had black skin when it was ripe. Consumers had gotten used to avocados turning black when ripe.

Gwen looks almost identical to Hass, except that its skin remains green. Even when ripe, Gwen is green. So consumers would be confused with some of their avocados turning black when ripe but others not. Would they let the Gwen sit on the counter until overripe because it was still green? This was the fear that handlers expressed. Handlers, also called packers, are those who buy fruit from farmers and then sell to retailers or other users.

Which is Gwen? Which is Hass? (Gwen left, Hass right)

Another way in which Gwen’s green skin was not desirable was that Florida avocado growers were the main competition for California growers at this time, and all of the avocados that came out of Florida were green. California could distinguish itself with black Hass fruit, as Hass does not grow well in Florida. 

The peel of Hass turning black as it ripens has one more advantage, which is to hide blemishes. As avocados ripen, they often naturally get a few brown or black spots on their peels, similar to the spots that form on the peel of a ripe banana. Even if the flesh underneath is perfect, it doesn’t look pretty from the outside. Avocados like Hass that turn black as they ripen hide these spots; they just blend in with the overall darkening peel.

Moreover, commercial avocados are put through an ordeal to get from tree to store shelf or restaurant. They are handled many times, refrigerated, and ripened with ethylene gas. These trials ensure that a green-skinned avocado like Gwen will ripen with dark blotches. Hass will too, except the blotches are concealed by its dark skin. Out of sight, out of mind.

You’ll note that, while this is beneficial for handlers and retailers, it is of little benefit to consumers. Green-skinned avocados allow consumers to make more informed purchases. For example, look at the two Gwen avocados below. Which would you buy? You would buy the one on the left that has no stem-end rot, of course. But if these were Hass, you wouldn’t be able to see that the one on the right has stem-end rot.

Fruit drop

The second most common problem with Gwen that I’ve heard is that the trees drop fruit. One grower told me that the reputation of Gwen was that as soon as its fruit was ready for picking it would drop. Someone who worked on harvesting crews while Gwen was in its early years of expansion in commercial groves told me that he remembered being called to harvest a grove of Gwens only to arrive to find fruit all over the ground. This really spooked growers.

Further, this fruit drop issue couldn’t be counteracted by picking the avocados earlier. While Gwen avocados can taste good when harvested from a tree in Southern California in March, the fruit doesn’t look good as it ripens because its skin shrivels. In comparison, a Hass avocado picked in March will ripen without shriveling.

How was a grower to navigate this? While it was disheartening for farmers to see their avocados on the ground, buyers didn’t want avocados that shriveled when they ripened.

Young trees

Finally, some people have told me that young Gwen trees were hard to get going in the field. They didn’t grow as strongly out of the gate as compared to young Hass trees.

Young Gwen avocado tree in my yard.

This was partly because Gwen was more precocious. Even newly planted, waist-high trees would bloom and try to set fruit. Some Gwen trees would bloom before even leaving the nursery. And sometimes they would bloom so intensely that they shed their leaves. 

Fruitset on one of my Gwen trees.

Growers liked the idea of a precocious tree, one that made a bunch of fruit in its early years so they could get an early return. However, the young Gwen trees seemed incapable of managing their own precocity.

Where the Gwen trees were grown without much stress, this wasn’t a problem. For example, at the University of California’s research station in Irvine, young Gwen trees performed wonderfully as the location was neither hot nor cold, the soil was a deep sandy loam, and the water was of good quality (at that time).

However, in less hospitable locations, under the watch of less attentive farmers, young Gwen trees sometimes struggled.

More about . . .

These were the most common reasons that I have encountered while seeking an explanation for Gwen’s disappearance from commerce. However, they don’t thoroughly satisfy me, and they beg for elaboration and context.

More about green skin

If consumers wanted only black-skinned Hass, then why did the University of California select the green-skinned Gwen for patenting in the first place? In fact, Gwen was one of three varieties that were patented and released in 1984, and all three were green. (The other two were Esther and Whitsell.)

This is partly explained by the fact that although Gwen was released in 1984, the variety was the product of an avocado breeding venture that began almost thirty years earlier, in 1956. That’s when Bob Bergh began searching for improved avocado varieties at the Citrus Experiment Station in Riverside, now the University of California at Riverside. And at that time, Hass was not the major commercial avocado variety in California. Fuerte was. And Fuerte is an avocado with green skin. (See, “Avocado Breeding in California.”)

Fuerte among other avocado varieties.

Fuerte satisfied everyone, from grower to handler to eater, in most ways. The fruit was about the ideal size, had a long harvest season, and tasted excellent. The main complaint came from growers, and it was that Fuerte trees did not bear enough fruit consistently.

Therefore, Bergh wrote in 1961 that the aim of his program could be stated in an oversimplified way as to be looking for: “A Fuerte that bears dependably.” (See, “Breeding Avocados at C.R.C.”)

During the 1960s and 1970s, Hass was grown more and more in California and elsewhere. It was a variety that clearly had great potential, as it was delicious and it fruited relatively consistently. Yet it was unclear how popular Hass could become because of its skin. As an Israeli grower wrote in 1965, “The Hass carries well to distant markets and tops even the Fuerte in quality, but its well known drawback is its black and warty surface.” (See, “The Avocado in Israel.”)

Consumers were beginning to accept Hass fruit due to its eating quality, but they didn’t appreciate its appearance. What was unappealing about black skin on an avocado? Black is the color of rotten spots on an avocado.

But what if you could find a variety that bore consistently like Hass and had great eating quality, but had green skin like Fuerte? Seems the best of both worlds. Eureka: Gwen fruits even more than Hass, is great eating, and is green like Fuerte.

Cluster of green Gwens.

This was the historical context in which Bob Bergh selected, patented, and released Gwen to growers.

Unfortunately, the desires of handlers were changing at the very moment of Gwen’s release. In 1985, David Freistadt, then president of Calavo (a large avocado handler), wrote, “. . . the industry has spent millions of dollars in an attempt to teach consumers that the Hass avocado turns dark — even black — as it reaches edibility. If we suddenly begin to market an avocado resembling the Hass but never turning dark, will our educated consumers let the avocado rot as they await its darkening as they have finally been taught? Or how much will we need to spend to re-educate without confusing?” (See, “An Appraisal of Gwen and Whitsell.”)

Many handlers had become so accepting of Hass that they were now interested in only Hass. “A monoculture is a marketer’s dream,” I heard one avocado handler say.

Gwen had been the right color when Bob Bergh began observing it (the seed was planted in 1963), but by the time he ushered it through the patent process and released it for commercial growing in the 1980s, it had become the wrong color. Gwen really was dead on arrival.

And the University of California breeding program has not patented and released a single other green-skinned avocado since Gwen. Lamb, Sir-Prize, Harvest, GEM – all black.

More about fruit drop

Over time it was discovered that Gwen’s habit of dropping fruit disappeared as trees matured. One grower told me the phenomenon ended after trees had been in the ground for more than three years. Another grower told me it took more like five years for the fruit drop to stop.

This behavior isn’t unique to Gwen. Lamb, a progeny of Gwen, acts the same way. Reed and Edranol do too. They drop fruit when nearing maturity while the trees are young but grow out of the pattern after a few years.

I know some Gwen trees that are decades old, and while they do drop a few fruit in the spring just before harvest time, the amount of drop is comparable to most other varieties.

Mature Gwen avocado tree.

Seeing fruit on the ground is never pleasing, but as one grower put it, “You have to count what’s still on the tree, not what’s on the ground.” And the ultimate yield on mature Gwen trees that I know are very high, at least as high as Hass. The tree in the photo above, for example, yielded approximately 1,000 avocados this past summer. I know because I harvested and counted them.

Nevertheless, I can understand the shock that it would cause a grower who had recently planted a few hundred Gwen trees to see a large portion of their first crops being shed and rotting on the ground, not knowing that it was only a juvenile problem.

More about young trees

Hass is usually an easier tree to grow from the start, it’s true. More precocious varieties like Gwen require more attention; they require better irrigation, possibly better fertilization, staking and training, and sunburn protection. Fruit might need to be thinned from a young Gwen tree. One has to protect the tree from its inclination to fruit itself into damage at a young age.

Young Gwen tree that is well-tended in a new grove in San Diego County.

But Gwen is by no means the first variety to require such attention. The old variety Lyon was known to bear “so precociously and so heavily that the tree is severely stunted and sometimes killed outright.” (See, “Breeding Avocados at C.R.C.”) And Pinkerton is similarly capable of stunting itself through fruiting too heavily too early.

Today we have GEM, another seedling of Gwen, which can also bloom so intensely at a young age that it sheds all of its leaves.

Hass, Gwen, and GEM: all ripe.

This characteristic of young Gwens and GEMs is a real challenge, and it seems inextricably linked to the variety’s precocity. Getting the trees through their first few years requires more care than less precocious varieties.

But here is the blunt take on this topic from Bob Bergh: ”If you can’t ensure good tree care, you probably shouldn’t be growing Gwens. (But then again, if you can’t ensure good tree care, should you be growing avocados?)”

In the end

Therefore, in my understanding, Gwen mainly failed commercially because it is green. Handlers preferred black avocados, Hass specifically.

To a lesser extent, Gwen was not embraced by more growers because young trees were trickier to grow and dropped some fruit, at least in some locations for some growers.

Were Gwen’s chances further hurt because of a hasty introduction into commerce? This idea was suggested to me by someone who worked within the industry at the time of Gwen’s release. What if the variety hadn’t been released until it had been trialed for longer in more varied growing situations (outside of university facilities)? Then Gwen’s fruit drop issue would have been seen to fade with tree age, the challenge of establishing young trees would have been no surprise. Growers could have started their Gwen plantings with more education, and therefore perhaps more success amid realistic expectations.

Maybe. But Gwen is still green.

So Gwen is primarily a backyard variety today. But it is a prized backyard variety. Everyone I know with Gwen plus other varieties in their yard or grove considers Gwen one of their favorites.

Sadly, Bob Bergh passed away last year. Gray Martin, who worked with Bergh for many years as his assistant, told me that Gwen was Bergh’s favorite variety until the very end. Gray added with humor, “Now, it was named after his wife . . .”

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