Pint of Camellia japonica Japanese Camellia White Masterpiece. Camellia japonica and most of its cultivars are considered to be winter hardy to USDA Zones 7-9. Even where winter hardy, unusually cold temperatures in winter (below 10 degrees F), particularly when occurring as a sudden temperature change, can damage or sometimes kill these plants. Japanese camellias may not be grown outdoors year-round in the St. Louis area (USDA Zone 6) except for a very limited number of recently developed cultivars that have displayed exceptional hardiness.