On Gardening: The Avocado

By Shirley Barker, Special to the Planet
Thursday February 18, 2010 - 08:48:00 AM

There are no vegetables I can think of that are eaten as fruits, although many fruits are eaten as vegetables. The tomato seems to me the fruitiest of vegetables. Chilis are fruits. All squash including cucumbers are fruits. If the eggplant, a fruit, is truly the king of vegetables, then its crown prince must surely be the avocado. Like many heirs to the throne, avocados have riveting love lives too. 

Persea americana’s full common name, avocado pear, is fruity, reflecting its shape. Although its origin and cultivation are tropical—native to Central America, widely cultivated in similar climates—it does well in sub-tropical Florida and California, including parts of Berkeley. A friend of mine who lives near the Claremont tunnel has a modest-sized tree that reliably produces quantities of avocados every year. I bet it might even grow in my cold, clammy plot. 

But would mine bear fruit? How often one hears the wail, “My avocado has flowered, but where are the pears?” or, “I have two avocado trees near each other and neither produces avocados!” That is because in order to avoid the self-pollination that might weaken its progeny, the avocado has an extraordinary mechanism called dianthesis, which gives it a schedule of preparing its flower parts to yield or receive pollen either in the morning or afternoon. If the tree’s neighbor has the same schedule, no pollination can take place. Of all nature’s reproductive strategies, this one is hardest to believe. Even A.B. Stout, author of a scientific explanation of this (Bulletin 257, The Pollination of Avocados, University of Florida), calls it remarkable. 

The avocado’s family, Lauraceae, is also quite exotic, with members such as camphor, cinnamon, and the culinary bay tree, Laurus nobilis. The bay trees in Tilden Park are of a different genus, Umbellularia californica. This native is much stronger in flavor than L. nobilis, and needs to be used with caution, as some people are allergic to it. Californian Indians used it as a medicine in various ways and ate the seeds, roasted. 

Nutritionally, avocado provides valuable amounts of protein, healthy fats, fat-soluble vitamin A, and the vitamins B. An avocado a day might be a very good idea. Unfortunately they usually cost at least a dollar apiece here, if not more. I do wonder why our city does not plant food trees in our median strips. Fewer people would go hungry. It seems particularly ridiculous that in California we should have to pay for lemons, oranges, and, why not, avocados. 

The avocado can be eaten as a dessert, a soup, and in the well-known guacamole dip, so called from the name used for avocado in most (but not all) Spanish-speaking countries, aguacate, and the word mole, for sauce. It is delicious plain, or sliced as a garnish. The best way to eat it, to my mind, is to slice it open and remove the large seed, which leaves a convenient cavity. Fill this with a little lemon or lime juice, olive oil, a sprinkle of sea salt crystals, and a few tiny pieces of tomato. Eat this ambrosia with a spoon. There are dozens of other recipes if this one palls, which I doubt it ever will for me.  

It can be worthwhile to grow trees from seeds and is certainly fun. Such a seedling is unique, and the grower can choose a name for it. An avocado seed will probably sprout if it is tossed into a compost bin, for they germinate readily. However, it is best to plant it in good potting soil, for its seeds, and skins, are toxic to many animals, including household pets, and I for one do not want to take a chance with my valuable pets, the composting worms. Plant the seed as soon as it has been removed, as it must not dry out. The time from seed to maturity can be as long as 10 years. It might or might not bear fruit. Commercial growers are not gamblers, so they propagate their avocados vegetatively, by grafting or budding known cultivars. 

Surely the attributes of the avocado make it an essential or at least a desirable part of the edible garden. It is a handsome shade tree, dropping its leaves to provide its own natural mulch and requiring no pruning. Sunset’s Western Garden Book lists a number of varieties appropriate for our growing zones, even one no taller than 10 feet. Most are considerably taller, and broad too. In stores, we mostly see the dark nubby Hass and the thin-skinned green Fuerte, a hybrid. Fruiting times vary, and when flowers form in winter, a sheltered spot is best, to protect them from frost and wind. It all depends on the micro-climate of one’s garden. In Berkeley, this can differ from street to street. 

According to some nutritionists and dermatologists, the avocado is beneficial to the skin, applied in a variety of ways, and when mashed, can safely be given to babies as an early semi-solid food. It even helps to maintain vision as we age. The list of its positive benefits seems endless, truly making it a royal vegetable. Or fruit.