Almost all macadamia nuts today are produced in Hawaii, most of them on the slopes of Mauna Loa, one of the two massive volcanic mountains that dominate the Big Island of Hawaii. Smaller orchards are on the islands of Maui, Kauai and Oahu. The Mauna Loa Macadamia Nut Visitor Center is five miles south of Hilo and 20 miles north of the Hawaii Volcanoes National Park on the Big Island of Hawaii. It sits in the midst of the company's 2,500-acre nut orchard. There's another large growing area near Papaikou on the Hamakua Coast as well.
Macadamias are tree nuts like pistachios, almonds and pecans.
Peanuts, by contrast, grow in the ground and are legumes. Macadamia trees are subtropical evergreens that grow to about 40 feet and have dark green leaves that resemble holly. The nuts start as green buds, which develop into sprays of white blossoms. Each spray produces two to 10 nutlets. There's a leathery outer husk, and inside is a hard brown shell, and inside the shell, the macadamia nut kernel.