Native to China, the calamondin is a relatively small and attractive citrus tree with 1-inch diameter fruits that look like little miniature tangerines, which are tart and tangy. A calamondin tree tolerates lower temperatures better than almost all other citrus and is cold hardy to 20 degrees in Zones 8 through 11. It is a good candidate for limited area landscapes and for container growing, and you can grow your own calamondin tree even if you don't live in a subtropical climate. If you're located in a cooler climate where sustained temperatures remain below 50 degrees, bring the calamondin indoors and set it back outside from about mid-April to mid-October.
Calamondin in Your Garden
Acclimate your newly acquired calamondin to the outdoors by setting it outside in a sunny spot early each morning. Do this every day for a week when all danger of frost has passed, and bring it inside around noon. Place it in a brightly lit spot out of direct sun for the rest of the day.
Set the calamondin outside first thing in the morning and bring it back inside at dusk for its second week. The plant can remain outside overnight when sustained temperatures remain above 55 degrees. Calamondins do not grow well below this temperature and may even insist upon going dormant.
Dig a hole that is a little wider than the calamondin's current container in a sunny, well-drained spot. Position the plant so that it will be at the same level it had occupied in the growing pot. Firm the soil around the root ball and add a little water now and then as you backfill the hole to eliminate air pockets.
Water the calamondin deeply and thoroughly. Water twice more in the following week, but only enough to evenly moisten the soil. Thereafter allow the top 1 inch of soil to dry out before watering again during the warm months of the plant's first year, but don't let its roots become dry. Next year, water only when the top 2 inches of soil have dried out. Although these trees are moderately drought tolerant once established, you should water deeply during extended dry periods.
Feed the calamondin with a slow-release 20-20-20 water-soluble fertilizer monthly during the growing season. Feed the calamondin at half strength during the winter months, but only every five to six weeks of the plant's first year. Continue warm-weather feeding in subsequent years, but you can stop further winter fertilizing thereafter.
Remove any young fruit that your calamondin tree produces before it's a year old. This will allow the plant to concentrate its energy and resources on branching out and strengthening its trunk.
Prune only if you see a dead limb or if shoots emerge on the calamondin's trunk. Nip the tips of branches only enough to maintain the plant's attractive shape.
Calamondin in Your Container
Place your potted calamondin tree in a very warm spot where it will receive as much direct sunlight as possible. A good choice is in front of a window with southeastern exposure. These plants thrive best at temperatures between 70 and 90 degrees.
Water when the top 2 to 3 inches of soil dries, but don't let the calamondin's roots become completely dry. Feed slow-release 20-20-20 water-soluble fertilizer at half strength once every six weeks.
Watch for fruit to appear after the calamondin tree begins to bloom, which can occur several times a year. Remove the fruit until the plant is a year old.
Prune any deadwood from the tree, and trim the tips of longer limbs here and there to keep the plant's shape neat and tidy. Remove shoots from the tree's trunk. Step the calamondin up a pot size only when it becomes root-bound.
Acclimate the calamondin to the outdoors after all danger of frost has passed by setting it outside in a sunny location every morning for a week. Let it stay out all day the following week, but bring it inside at dusk. The tree can remain outdoors overnight once sustained temperatures remain above 55 degrees.