The origins of the orange tree can be traced back to China. Orange trees are sensitive to cold, so they flourish only in a few regions of the United States. The trees grow in states with sub-tropical or tropical climates. The largest orange producing regions are Florida, Texas and California.
The Valencia orange is the most widely grown orange tree in the world, according to Texas A&M University. The tree was first introduced in Florida in 1870 from Portugal or Spain. Valencias are medium to large oranges with no seeds, which are popular for juice production. The fruit matures on the tree in February, but can remain hanging on the branches until summer, and will often re-green during spring. The peel of the Valencia orange is thin and easy to hand-peel. In Florida, the this orange accounts for 50 percent of the fruit crop, according to Southwest Florida Research & Education Center.
The satsuma mandarin orange (Citrus reticulata) was introduced in the U.S. in 1878 from Japan. Blossoms are produced from March to April and fruit production is ready for harvest in October. The tree is exceptionally cold hardy, and can withstand temperatures that plummet to 26 degrees F. The trees are commonly grown in containers and rarely exceed 6 feet in height. Their small size makes them an ideal patio orange tree. Fruits measure only 1.8 inches in diameter and are exceptionally sweet.
The ambersweet orange is a citrus hybrid that was developed by Dr. C. J. Hearn of the U. S. Department of Agriculture Horticultural Research Station in Orlando, Florida, according to the University of Florida. It was obtained by crossing a Clementine tangerine and an Orlando tangelo with a seedling of a mid-season sweet orange. The ambersweet was developed in 1963, but its official release was in 1989. It is an early harvest orange with excellent color. The fruit contains from 0 to 30 seeds and is quite sweet. These oranges can be easily hand-peeled.
The Hamlin orange is the most widely grown sweet orange in the state of Florida, according to the Southwest Florida Research & Education Center. The tree offers exceptional cold hardiness, and is harvested early in the season. It offers high fruit yields per acre. Unfortunately, the fruit of the Hamlin orange is prone to splitting, which makes it unsightly, and it is affected by late season dropping. Hamlin fruit is a popular orange for juice production because it's often visually unappealing for home fruit commercial sales.