Few New World plants growing at the San Francisco Botanical Garden have the long history of
cultivation and modern, international renown as the avocado. A native of Mexico and Central America, evidence that the avocado has been cultivated for food dates back 10,000 years, and it is believed that prior to this time they were eaten as a wild fruit for at least 2000 years. A member of the laurel family, the avocado is a relative of other popular aromatic plants used as foods, including cinnamon, bay laurel, and sassafras, the North American species of the latter serving as the main flavoring agent of traditional root beer and sasparilla.
Cultivated avocados differ little from their wild relatives, unlike many of our cultivated fruits, vegetables, and domesticated animals. Recent research suggests the wild avocados of Mesoamerica had attained their relatively large size prior to the arrival of humans in this area, and perhaps evolved with now-extinct megafauna (large animals) living tens of thousands of years ago. The large, relatively unprotected fruit, a pulp that contains laxatives, and a seed that is bitter and toxic if broken, suggest that the fruit was swallowed whole, and that the seed passed quickly through the large animal’s digestive tract without damage to be deposited elsewhere in the animal's feces to germimate and grow a new tree. In regions of Africa today where Persea americana is cultivated, elephants consume the fruit and disperse the seeds in this very way.
There are more than 150 species of avocado around the globe, from the US, Mexico, Central and South America to the Canary Islands, Africa, and into Asia. In spite of the diversity of species internationally, Persea americana is the primary species used as food for humans around the globe. In Mexico alone there are 12 species of avocado, but most are inedible.
Nutritionally, avocados are rich. Relative to most other fruits, the avocado is high in unsaturated fat — the "good" fat — which lowers cholesterol. They're calorie rich — averaging 250 calories for a medium-sized fruit. They're also high in potassium (helps control blood pressure), lutein (good for your eyes), and B, C, and E vitamins. They're also low in sugar and contain fiber.
Though our two specimens are yet to fruit, they do currently produce small flowers. We keep our eyes on them annually, with the hope that they will soon fruit for us here in the Garden.
IN BLOOM CONTRIBUTORS: Text by Corey Barnes and Profile by Mona Bourell. Photos by Joanne Taylor.