Mandarin oranges (Citrus reticulata) varieties of which are known as mandarins, tangerines or satsumas, are far more cold-hardy compared to the common orange (Citrus x sinensis), a fruit with subtropical and tropical origins. Mandarins cannot be grown in mountains or regions with continental winters, but with precautions against sudden drops below freezing, they can typically be grown in U.S. Department of Agriculture plant hardiness zones 8b through 11.
Cold Hardy Mandarin Oranges
Temperatures of 26 to 28 degrees Fahrenheit will damage standard orange species. If they’ve become acclimated to the cold, the most cold-hardy mandarin oranges, Satsuma (C. unshiu) and “Changsa” (C. reticulata “Changsa”) can endure temperatures as low as 15 F. A plunge in temperature to 20 F after a period of low temperatures can cause less damage than a drop to 25 F subsequent to warmer weather. Trees less than 2 to 3 years old are much less cold-hardy as those bearing oranges.
The Satsuma mandarin, also referred to as the Satsuma tangerine is the most cold-tolerant mandarin cultivar grown commercially and might be the wide variety of choice for those in USDA zone 8b. Mature Satsuma trees have survived winter temperatures of 14 to 18 F with no severe damage in southern Alabama, northern Florida and northern California. They may be grown from the Sacramento-San Joaquin Valley basin of California, in northern Florida and the Gulf Coast.
The “Changsa” mandarin is maybe most cold-hardy of all sweet orange species. The “Changsa” orange returns sweet, but insipid and seedy oranges which are an excellent orange-red. It has survived temperatures as low as 4 F in Arlington, Texas. “Changa” mandarins are most cold-hardy if they’re grown from seed.
Growing Mandarins in Marginal Climates
Orange trees are evergreen and can bear both fruit and flowers at precisely the same time. Since they store food reserves in their leaves, they still have to be protected from temperature drops that can cause their leaves to drop. Small changes in distance from the shore or at elevation can greatly influence minimum temperatures for growing mandarin oranges. With caution, you can develop them farther inland, farther north and at higher elevations than standard orange cultivars. If you reside at the edge of the area acceptable for growing mandarin oranges, then plant them in hot areas on the sides or hills or around buildings. Mountain foothills often contain small protected areas appropriate for growing mandarins.