In the Unites States, pomegranate trees, native to southern Asia, primarily grow in California and Arizona, where the subtropical climate best meets the plant's needs. Pomegranate trees prefer cool winters and hot summers, but humidity causes the tree to produce less fruit. The trees also grow in containers as long as they receive protection from frost and cold weather.
Most pomegranate trees grow up to 16 feet in height, although some may reach 30 feet. The deciduous tree grows as a tidy, rounded shrub with reddish-brown bark and stiff, spiny branches. One-inch scarlet or white flowers appear at the ends of the branches. Insects easily reach the blossoms to play a role in helping to pollinate the plant. Once the flowers fade, the fruit begins to grow, reaching up to 5 inches in width when mature, about five to seven months after flowering. The fruit features a tough, dry yellow skin overlaid with a pink or red hue. Pomegranate trees may live more than 200 years, although their fruit production drops after about 15 years.
Pomegranate trees need plenty of hot days to get the best flavor from the fruit. They also require plenty of sun in the warmest part of the garden. Once established, pomegranate handles drought well, but it requires plenty of water to produce tasty fruit.
Plant pomegranate trees in well-drained soil to provide ideal conditions. The plants also grow in acidic, gravelly or calcareous soil. New pomegranate trees need regular watering until they get established. The plant may produce fruit one year after planting, although two to three years is more common. Pomegranates planted in containers need daily watering during the hottest days since the soil dries out so quickly.
Pomegranate trees require very little fertilization after the first few years. During the plant's first two years, the trees grow well with 2 to 4 ounces of ammonium sulfate or some other type of nitrogen fertilizer. Consider adding a layer of mulch or compost each year.
When the trees reach 2 feet in height, they need to be cut back. This allows shoots to develop. Allowing four or five shoots to develop, evenly spaced around the stem and about 1 foot from the ground, helps give the tree a well-defined trunk. During the first three years, consider shortening the branches to encourage more new shoots on all sides. Since the fruit grows only on the end of new growth, this helps provide more branches on which the fruit might appear.
Ripe pomegranate fruit makes a metallic sound when tapped. Once ripe, collect the fruits immediately since rain cracks them open if they stay on the tree too long. The fruits store well at temperatures of 32 to 41 degrees Fahrenheit for up to seven months. Unlike most fruits, pomegranates get juicier and more flavorful in storage.