Ranch of a Thousand Gems. The ‘GEM’ variety can grow anywhere in the world where growing conditions are similar to Southern California's (San Diego–San Luis Obispo Counties). The seasonality of ‘GEM’ is somewhat later than that of ‘Hass,’ allowing for a later start of harvesting and subsequently a later marketing window. In California, the fruit will hang on the tree very well into August and early September. In cooler places, like coastal Santa Barbara, Calif., it can hang on the tree until October.