The yuzu (Citrus ichangensis × C. reticulata) is a citrus fruit and plant originating in East Asia. It is believed to be a hybrid of sour mandarin and Ichang papeda. The fruit looks somewhat like a grapefruit (though usually much smaller) with an uneven skin, and can be either yellow or green depending on the degree of ripeness. Yuzu fruits, which are very aromatic, typically range between 5.5 and 7.5 cm in diameter. It is unusual among citrus plants in being relatively frost-hardy, due to its cold-hardy C. ichangensis ancestry, and can be grown in regions with winters at least as low as -9 °C (15 °F) with no decrease in fruit quality. It tastes heavily of its grapefruit parentage with wonderful overtones of mandarin orange.