The Camellia genus encompasses more than 2,300 different cultivars with a seemingly endless assortment of flower colors and shapes. They are broadleaf evergreen flowering shrubs native to Asia. Different types are cultivated for their large flowers as well as for climate and cold tolerance. The tea plant species, Camellia sinensis, where many green, black and oolong teas come from, is a member of this genus and can be grown for harvest or as an ornamental plant.
Each year the American Camellia Society registers new cultivated varieties, called cultivars, adding new types of camellias to the already extensive list. Many of the cultivars come from several types. Cultivated varieties come from single species that are bred for a desired trait, usually flower color or appearance. Hybrid cultivars are a combination of two different types of camellias that are bred together.
Camellia japonica, or Japanese camellia, is a common species in this genus that has large flowers with multiple petals, creating large, fluffy looking blossoms. Camellia sasanqua, or Christmas camellia, has smaller flowers with simple petals that lack the flouncy look of the Japanese camellia but make up for it with delicacy. Similar to the Christmas camellia but with smaller leaves is the common species Camellia oleifera, or tea-oil camellia.
Most types of camellias are best suited for mild climates, though they can tolerate some winter frosts when planted in protected areas. In cold climates, camellias can be grown in large planters and brought indoors for the winter. The flowers bloom in late winter and early spring and fade before the heat of summer arrives.
For the cold climate gardener, horticulturalists have developed types of camellias that flower in the fall rather than winter and can survive in colder climates. These cold climate cultivars include hybrids of the Camellia oleifera. This type of camellia is cold hardy but does not present the large blossoms coveted by gardeners. To create a cold-hardy plant with large showy blooms, the Camellia oleifera was crossed with the Camellia sasanqua.
Camellias grow well in protected areas of the garden or landscape where the plants are sheltered from direct sunlight and wind. A spot that has soil with good drainage and high organic matter helps keep camellias healthy and blooming abundantly. These plants benefit from consistently moist soil, and a layer of mulch spread 2 to 4 inches (about 5 to 10 cm) deep around the base of each plant helps keep the soil damp and regulates the soil temperature.