{"id":21231,"date":"2024-08-16T18:15:50","date_gmt":"2024-08-17T01:15:50","guid":{"rendered":"https:\/\/gregalder.com\/yardposts\/?p=21231"},"modified":"2024-08-16T18:34:55","modified_gmt":"2024-08-17T01:34:55","slug":"the-sharwil-avocado-tree-a-profile","status":"publish","type":"post","link":"https:\/\/gregalder.com\/yardposts\/the-sharwil-avocado-tree-a-profile\/","title":{"rendered":"The Sharwil avocado tree: a profile"},"content":{"rendered":"\n

Sharwil is Australia\u2019s most important contribution to the world of avocados. It\u2019s an exquisite fruit that has impressed all from the start. In 1961, Stanley Shepard, a leader of the California avocado industry, visited the continent down under and reported<\/a>: “The most promising Australian fruit that I saw was the Sharwil.”<\/p>\n\n\n\n

Fruit characteristics<\/strong><\/p>\n\n\n\n

To my taste, Sharwil avocados are just right. They are medium size, not too big and not too small. Their skin is green, whether ripe or unripe, and it is medium in thickness, not thin enough to split while on the tree like Stewart and not too thick so it\u2019s hard to tell when they\u2019re ripe like Nabal. And the skin is bumpy, and it peels well.<\/p>\n\n\n\n

Inside, the flesh has no fiber; it is green and golden yellow. The flavor is neither weak nor strong, it is just a good avocado flavor, similar to Hass or Fuerte. But usually the flavor is slightly milder than those, more like the flavor of Edranol.<\/p>\n\n\n\n

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Where Sharwil rises above is with its small seed, smaller than Hass or Fuerte or Edranol.<\/p>\n\n\n\n

Harvest season<\/strong><\/p>\n\n\n\n

The earliest I have eaten a good Sharwil is February, and the latest is May. This is for fruit grown in inland San Diego County. For comparison to other varieties grown in this same region, Sharwil tastes good later than Fuerte but earlier than Hass.<\/p>\n\n\n\n

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Sharwil among other varieties, harvested in late April in San Diego County.<\/figcaption><\/figure>\n\n\n\n
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Sharwil among other varieties, harvested in late July in Orange County.<\/figcaption><\/figure>\n\n\n\n

When W.B. Storey took a trip to Australia in 1960<\/a> and observed Sharwil for the first time, he reported back to fellow Californians: \u201cThis appears to be a very fine fruit which matures later than Fuerte and about the same time as Hass.\u201d<\/p>\n\n\n\n

But in 1960, Sharwil was a very new introduction, and only one year later an Australian named George Schulz wrote<\/a> that the Sharwil harvest was \u201cjust before the Hass.\u201d Sharwil was still being figured out then.<\/p>\n\n\n\n

Variety history<\/strong><\/p>\n\n\n\n

Sharwil is the creation of Frank Sharpe<\/a>, who was a pioneer of avocado farming in Australia, starting near Brisbane in 1946. Sharpe grew local varieties but also imported trees of all the best California varieties from Armstrong Nursery, then based in Ontario, San Bernardino County. And from the beginning he grew out seedlings in search of improved varieties. In 1954, he introduced the Sharwil, which he had crossed at his Redland Bay farm in 1948-49.<\/p>\n\n\n\n

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Sharwils on a tree in late January in California, about ready for picking.<\/figcaption><\/figure>\n\n\n\n

The parents of Sharwil are unknown, but if you’ll allow me to speculate . . . I think that Edranol<\/a> is one of them. The leaves of the trees of the two varieties have a similar spade-like shape. The fruit of the two varieties have similar skin color, thickness, and pliability; the flesh of both is fiberless and tastes similar; and the seeds of both varieties have a tendency to hold onto a little flesh when the fruit is cut open. Further, Sharpe lists Edranol<\/a> as one of the main varieties he grew on his Redland Bay farm at the time he grew the seedling that became the mother Sharwil, and no other of his listed varieties bear as much resemblance.<\/p>\n\n\n\n

“Sharwil” is a portmanteau, combining the names Sharpe and Wilson. James Wilson was in a farming partnership with Frank Sharpe<\/a>, and he later bought from Sharpe the Redland Bay farm where the variety originally grew.<\/p>\n\n\n\n

In the 1950\u2019s, Sharwil was brought to California but, as Stanley Shepard of Carpinteria wrote in 1970<\/a>, here \u201cit does not seem to do as well as it [does] in other parts of the world.\u201d<\/p>\n\n\n\n

In 1977 in Queensland<\/a>, three varieties dominated avocado plantings: Fuerte, Hass, and Sharwil.<\/p>\n\n\n\n

But by 1990, Sharwil was \u201closing popularity among growers in most areas [of Australia] because of erratic production,\u201d wrote D.W. Lavers<\/a>.<\/p>\n\n\n\n

Investigations into the erratic production of Sharwil in Australia turned up an explanation that had been known for decades<\/a>. Sharwil has a B-type flower, and B types are generally less productive in some climates than A types because they are more sensitive to cool temperatures during flowering. (See also Peterson, 1965<\/a>.)<\/p>\n\n\n\n

Sharwil doesn\u2019t have this problem where nights are warm, such as in tropical areas. On Hawaii\u2019s Big Island, particularly in the Kona district, Sharwil became the variety that avocado farmers chose for commercial production and export starting in the 1980\u2019s. Unfortunately, from then until today, the USDA has gotten in their way and banned the movement of Sharwils from Hawaii to the mainland on and off through fruit fly regulations.<\/p>\n\n\n\n

Nevertheless, the association of the Sharwil variety with the Kona district became strong enough for some growers and nurseries in California to start referring to the variety as \u201cKona Sharwil.\u201d<\/p>\n\n\n\n

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Nursery tag for a “Kona Sharwil” avocado tree in California.<\/figcaption><\/figure>\n\n\n\n

The irony is that I\u2019ve never heard a grower in Hawaii refer to the variety that way.<\/p>\n\n\n\n

(See McDonald, 2010<\/a> and Bevacqua, 1994<\/a> and Hawaii Avocado Association<\/a>.)<\/p>\n\n\n\n

Sharwil avocado tree characteristics<\/strong><\/p>\n\n\n\n

Leaves and stems<\/strong><\/p>\n\n\n\n

I don\u2019t have firsthand experience with Sharwil trees in Hawaii or Australia, but I do have firsthand experience with them in California. I\u2019ve grown a handful of my own, and I\u2019ve seen many more elsewhere.<\/p>\n\n\n\n

Sharwil trees have gorgeous foliage, with large leaves that are deep green. They are prettier than many other varieties to me, as pretty as a Bacon.<\/p>\n\n\n\n

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Sharwil leaves.<\/figcaption><\/figure>\n\n\n\n

The young stems have red flecks, especially if they\u2019re growing rapidly such as on a tree that has been grafted to a large rootstock.<\/p>\n\n\n\n

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Red flecks on stems of new growth of Sharwil tree.<\/figcaption><\/figure>\n\n\n\n
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Totally red stems of rapidly growing shoots of Sharwil grafts onto mature rootstock.<\/figcaption><\/figure>\n\n\n\n

The leaves of Sharwil do not smell of anise if crushed, as the leaves of some other avocado varieties do.<\/p>\n\n\n\n

Architecture<\/strong><\/p>\n\n\n\n

Sharwil trees have spreading canopies; they\u2019re not drooping like GEM nor are they upright like Zutano. They grow similarly to Hass, except that they more often send out long branches that later sag, especially if they’re carrying fruit.<\/p>\n\n\n\n

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Typical spreading canopy on a Sharwil tree.<\/figcaption><\/figure>\n\n\n\n
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Another typical rounded canopy on a Sharwil tree.<\/figcaption><\/figure>\n\n\n\n
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This Sharwil tree is the most upright one I’ve ever seen.<\/figcaption><\/figure>\n\n\n\n

Sharwil’s canopy shape is partly due to the fact that its branches don’t make as many side branches as some other varieties. Trees that make branches with many side branches (“sylleptic” growth) look more dense and are less vulnerable to sunburn. Reed, Edranol, Cadway, Carmen, and Gwen are examples of varieties with much sylleptic growth, denser canopies, and less sunburn vulnerability compared to Sharwil.<\/p>\n\n\n\n

(See an academic analysis of this tree architecture topic by Thorp and Sedgley<\/a>.)<\/p>\n\n\n\n

Sharwil’s branch architecture is not a problem in a mild climate, such as one near the beach. But it is annoying to a grower in a location with strong sun, as it requires one to frequently cut short such long branches (“head” them) or else accept sunburn, which will later impair the vigor and productivity of the sunburned branch.<\/p>\n\n\n\n

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Long Sharwil branch that became sunburned so I headed it back and now it is sprouting new growth.<\/figcaption><\/figure>\n\n\n\n

Heat and cold tolerance<\/strong><\/p>\n\n\n\n

In this way, Sharwil is not as suited to locations with hot summers as well as some other varieties. (This isn’t to say that Sharwil can’t be grown successfully in a hot climate though.)<\/p>\n\n\n\n

In terms of cold tolerance, I have found Sharwil to be no weaker or tougher than Hass.<\/p>\n\n\n\n

Productivity<\/strong><\/p>\n\n\n\n

The Sharwil tree\u2019s fruitfulness is the most important quality to consider. Here in California, Sharwil is simply hit-and-miss.<\/p>\n\n\n\n

First, some young Sharwil trees are slow to begin making avocados. I have one that is six years old and yet has barely made flowers and has not produced a single fruit whereas I have trees of other varieties of the same age that have already made dozens. I have heard reports from others with similarly indolent Sharwils.<\/p>\n\n\n\n

But I do know of a few young Sharwils that have produced, and I have seen Sharwil trees that were made by grafting onto mature rootstocks and some of those trees set good crops within two years of grafting.<\/p>\n\n\n\n

Sharwil\u2019s fruitfulness is most closely related to where it is growing. As mentioned above, Sharwil has a B-type flower, which needs warmer weather to make fruit compared to A types.<\/p>\n\n\n\n

(Sedgley and Grant<\/a> published a study on this phenomenon in 1983.)<\/p>\n\n\n\n

Therefore, if a Sharwil tree is grown in a cool location, it is unlikely to produce as much fruit through the years compared to most A types. And a Sharwil tree will not produce much fruit in a given year if that year has weather that is too cool in spring, no matter the location. (The past two springs, 2023 and 2024, have been cooler than average in Southern California, especially 2023.)<\/p>\n\n\n\n

An illustration of this is seen in an avocado tree that I have with a dozen or so varieties grafted on, including Sharwil. During this past cool spring of 2024, the Sharwil branches flowered heavily but did not set a single fruit. At the same time, some other B varieties flowered well and they also did not set any fruit. On the other hand, most of the A varieties set fruit, and some set so much that I had to thin their branches to prevent them from breaking.<\/p>\n\n\n\n

But to reiterate, Sharwil’s fruitfulness depends a lot on the location. During this same cool spring of 2024, this Sharwil tree in a warmer location about ten miles from me performed quite differently:<\/p>\n\n\n\n

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Young Sharwil fruit growing in August, set during spring 2024. <\/figcaption><\/figure>\n\n\n\n

Should you grow a Sharwil tree in your yard?<\/strong><\/p>\n\n\n\n

I would not choose Sharwil as my yard\u2019s only avocado tree. I would choose a more reliable fruiter for that, such as Hass or Reed. But if I had space for multiple trees I would add Sharwil, especially if my yard were warm enough to get good production from a B-type avocado.<\/p>\n\n\n\n

How to know if your yard is warm enough? If you see frost on the ground in your yard many times every winter, then it’s not best for Sharwil or any other B type. (Here is a presentation<\/a> on the topic that gives more specific information.)<\/p>\n\n\n\n

Sharwil can make a nice addition to a yard’s avocado trees because it fills the harvest window of late winter into spring. I know of no other variety that is as enjoyable to eat during this window.<\/p>\n\n\n\n

Sharwil\u2019s legacy<\/strong><\/p>\n\n\n\n

Sharwil is not grown much commercially in Australia anymore. Sharwil never impacted the commercial avocado industry in California. Yet Sharwil has been in high demand from backyard growers in California for the past decade or two primarily because of the influence of members of the Orange County chapter of the California Rare Fruit Growers. They shared about the virtues of the Sharwil fruit and they grafted Sharwil trees to spread around.<\/p>\n\n\n\n

I would guess that here in 2024 there are more Sharwil avocado trees growing in California dirt than ever before, 80 years after the variety was first brought to American shores, even though almost none of them are growing on farms.<\/p>\n\n\n\n

Some avocado breeders have tried to develop a tree with a Sharwil-like fruit that produces better. Even though Sharwil produces relatively well in Hawaii, breeders at the University of Hawaii aimed toward better production with their release of a seedling of Sharwil they called Greengold<\/a>. Although Greengold has an A flower and fruits more in some of the trees I\u2019ve seen, I don’t think the Greengold avocado quite reaches the heights of Sharwil eating quality.<\/p>\n\n\n\n

David and Judi Grey of New Zealand have selected three seedlings of Sharwil from a 1999 planting that they call the \u201cAvogrey\u201d varieties. Each is a greenskin, and it is said<\/a> that they are of good eating quality and produce \u201cregular crops.\u201d<\/p>\n\n\n\n

Perhaps the Greys have landed on an improved Sharwil. We can hope. (I have not eaten these varieties nor seen the trees in person.)<\/p>\n\n\n\n

For now, we will be grateful for how good Sharwil avocados are to eat whenever the trees bless us with them.<\/p>\n\n\n\n

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My video profiles of the Sharwil avocado:<\/p>\n\n\n\n