Every Hass Avocado Is a Cutting From One California Tree

Rudolph Hass was a postal worker who kept a small avocado grove on West Road in La Habra Heights, California. In 1926 he bought three Guatemalan-strain seeds from a local nurseryman named A. R. Rideout, planted them, and got one strong seedling. He intended to use it as rootstock for a grafted Fuerte tree — Fuerte was the dominant cultivar of the day. The graft kept failing. Hass tried again. It failed again. His son later wrote that he was about to cut the tree down when his children begged him to leave it alone and let it fruit on its own.

The fruit, when it came, looked wrong. Where Fuerte avocados were smooth and bright green, Hass's were small, lumpy, and turned almost black as they ripened. But people who tasted them preferred them. The flesh was oilier, denser, and richer. The skin was thick enough to ship across the country without bruising. Hass patented the cultivar in 1935 — the first US patent ever issued on a tree — and licensed propagation rights to a nursery for one cent per seedling.

Here is what makes the story strange. Avocados do not breed true from seed; the offspring of a Hass tree are a genetic shuffle and almost never make commercial fruit. So the only way to grow a Hass is to cut a budwood twig from an existing Hass tree and graft it onto rootstock. Every commercially grown Hass avocado on Earth — about ten million trees in groves from California to Peru to Israel — is a clonal descendant of that one stubborn seedling at 430 West Road.

The original tree died of root rot at age 76 and was cut down on September 11, 2002. Two small plaques mark the spot in front of a private home. The cultivar that started there now accounts for roughly 80 percent of all avocados eaten worldwide.