- Calamondin × Citrofortunella microcarpa (Bunge) Wijnands Rutaceae

Species description Calamondin is an upright, cylindrical citrus tree with dense, small, glossy, evergreen leaves. Fruits are small, round, and at maturity, and contain many seeds. The fruit rind is thin, finely pitted, and smooth. Inside, the flesh is tender, acidic, and very juicy. Calamondin trees flower and set fruit throughout the year, and are a decorative, edible tree that may be grown in pots. Outside, in good growing conditions, calamondin trees can grow 20-30 feet high and live for more than 50 years. Calamondins are more cold tolerant than any other true citrus species, but they are still limited to low desert regions in Arizona.

Natural and cultural history Calamondin trees are of Chinese origin, and the fruit was distributed early and widely throughout Orient, including Indonesia and the Philippines. The trees were introduced to the U.S. as an "acid orange," circa 1900. The tree has since found a market as an ornamental, though the acidic fruit also has many culinary uses.

Planting considerations and propagation techniques Calamondin trees prefer full sunlight and space to grow, however, they can also be grown quite well in containers or small garden spaces. Flowers are self-fertile and require no cross- pollination, though honeybees effectively pollinate flowers. Citrus can grow on a wide range of soil types, from sand to loam to heavy clay as long as they are well drained. The ideal soil pH for citrus trees ranges from 6-6.5. Calamondin trees may be easily grown from seeds or from rooted cuttings. Common grafting techniques for citrus are T-budding or chip-budding. Budding should be practiced when seedling stems are roughly the size of a pencil and when bark of the rootstock is slipping. Budwood should be collected from healthy trees and should be about the same diameter as the rootstock. Budding season takes place immediately before spring growth. A seedling tree will produce a crop of fruit at the age of two years and will continue to bear nearly year round.

Water needs Citrus need about 4-6 inches of water per month in the summer. Calamondin trees are slightly more drought tolerant than most citrus.

Care Citrus trees should be trained to a suitable shape with an open center. There are three primary pruning objectives: increase total leaf area, improve airflow through the canopy, and increase light to the branches. Proper training keeps trees the correct size for ease of care and harvest. Citrus are prone to many diseases and pests. We recommend consulting a Cooperative Extension citrus specialist. (See Yuma Cooperative Extension, https://extension.arizona.edu/yuma; and http://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1492.pdf).

Harvesting and processing Calamondin fruits are small and thin-skinned, best used within a week after harvest if not refrigerated. When picking the fruit, use clippers or scissors to cut the fruit from tree, rather than pulling them. This will keep the stem end of the fruit from tearing, which promotes deterioration. Calamondin juice can be used like or juice to make refreshing beverages, flavor fish, to make cakes, marmalades, pies, preserves, sauces and to use in soups and teas. Juice is best in acid beverages and desserts.

References and resources AZ Citrus. http://www.azcitrus.com Gmitter, F.G., J. Soneji, M.N. Rao, and S. Huang. Citrus spp., pp. 773-784. Eds. Janick, J. and R.E. Paull. The Encyclopedia of Fruit and Nuts. CABI Publishing, Cambridge, MA. Morton, J. 1987. Calamondin, pp. 176–178. In: Fruits of warm climates. Julia F. Morton, Miami, FL. https://www.hort.purdue.edu/newcrop/morton/calamondin.html Page, M. 2008. Growing Citrus: How to Grow Citrus in Containers, Conservatories, and the Open Garden. Timber Press, Portland, London. Plants for a Future (PFAF). n.d. Citrofortunella microcarpa - (Bunge.)Wijnands. http://www.pfaf.org/user/Plant.aspx?LatinName=Citrofortunella+microcarpa Soost, R.K. and M. Roose. 1996. Citrus, pp. 257-324. Eds. J. Janick and J.N. Moore. Fruit Breeding, Volume I Tree and Tropical Fruits. John Wiley & Sons, New York, NY. University of Arizona Cooperative Extension. 2000. Irrigating citrus trees, publication AZ 1151. http://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1151.pdf University of California at Riverside. Citrus Variety Collection. Calamondin. http://www.citrusvariety.ucr.edu/citrus/calamondin.html Useful Tropical Plants. 2016. Citrofortunella x microcarpa. http://tropical.theferns.info/viewtropical.php?id=Citrofortunella+x+microcarpa

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