The hybrid calamondin orange tree, or X Citrofortunella microcarpa, was created by crossing the mandarin tree, or Citrus reticulata, with the kumquat tree, or Fortunella margarita, according to Floridata. The evergreen calamondin grows approximately 25 feet in height with a shrub-like appearance due to the branches that grow low on the trunk. The branches are covered with abundant thorn-like spikes.
The fruit of the calamondin is considered to be an acid orange due to its bitter taste. It is quite small, averaging only 2 inches in diameter. The fruit ripens throughout the fall and winter months and is widely used in drinks or as a garnishment. Fruit is created on the tree year-round, but harvest generally takes place in November and December.
The tree produces abundant fruit and flowers when grown in full sunlight, but will tolerate partial shade. It is a popular container plant in tropical regions, where it is placed beside pools and patios.
The calamondin grows an exceptionally long taproot, which allows it to tolerate drought spells. Water the tree deeply. It enjoys moist soil conditions. Apply 3 to 4 inches of mulch around the base of the tree to help the soil maintain moisture during the heat of summer.
The calamondin is a cold-hardy citrus tree that can easily withstand a temperature dip to 20 degrees Fahrenheit. Unlike other orange trees, it grows well in the U.S. Department of Agriculture's Zone 8B. Its fruit stores for up to two weeks if the temperature after harvest is maintained between 48 degrees to 50 degrees Fahrenheit.
Harvest fruit that appears firm with a yellow-orange color. Always clip the fruit from the tree using pruning shears because the skin of the calamondin is quite thin and easily damaged. Each calamondin contains 12 calories, according to the University of Florida. Each fruit contains five to nine segments when peeled.