Growing Pomegranate Trees
Metus dictum at tempor commodo
Recent studies support historical claims that pomegranates promote health as much as they delight taste buds. For gardeners, the benefits are easy to harvest. Pomegranates bear early and suffer from few diseases or pests. Orchardists seeking a market niche can choose from among more than 1,000 diverse cultivars, nearly all of which are unavailable to grocery store customers.
How Do Pomegranates Grow?
Pomegranates should be on all lists of the best fruits for organic gardeners because they’re so easy to grow. Animals and insects leave the fruit alone thanks to its tough rind. Unlike peaches and cherries, these tall deciduous shrubs rarely require spraying in small orchards or home gardens. Pomegranates can tolerate high temperatures of up to 118 degrees Fahrenheit, and a few cultivars can handle exposure to minus 6 degrees without dying back to the ground. The shrubs prefer good garden soil, but will produce despite excessive salinity, calcium, and alkaline soil, and do well in drought or damp conditions.
For growers in Zone 7 or lower, though, pomegranates (Punica granatum) are a lesson in microclimates and cultivar selection. The best strategy is to buy the most cold-hardy shrub you can find, and plant it close to a building in a location that receives full sun. The difference between a plant that survives winter and one that dies can come down to its proximity to a stone or brick wall that absorbs the heat of the sun during the day and releases that energy at night. Alternatively, you can grow pomegranates in pots and bring them inside during winter.
Choose a planting site carefully. In cooler areas, the best fruit yield requires the warmest possible location. Growers usually plant close to the south or southeast side of a building, preferably made of stone or brick, to reduce winter wind exposure and provide a microclimate.
Dig a planting hole three times larger than the plant — at least 2 to 3 feet in diameter and 1 to 2 feet deep. Improve the soil with a bag or two of manure, and mix it into the hole with a shovel before planting. Water the hole well before planting, and again after you’re finished.
Although pomegranates can survive less-than-ideal conditions and still produce fruit, they respond best to attentive growing in an optimal setting. In Zones 8b to 10, they’ll flower and set fruit multiple times a year. Fruit set is affected by several factors, including the cultivar and its proportion of female flowers to male; cross-pollination between different cultivars, which can increase fruit set 20 to 40 percent; irrigation or rainfall; and fertilizer application. Gardeners can prune moderately for fruit productivity and to maintain a graceful weeping form. Otherwise, only dead or awkward wood need be removed.
Experts disagree on the value of starting a new pomegranate shrub from seed, but most agree that the seeds can’t produce true-to-type plants.
Instead, take an 8-to-20-inch-long cutting at least as thick as a pencil from a vigorous, healthy plant. You can even dig out unwanted suckers or cut branches to open up the canopy of an existing plant. Mark the base end with a crayon or pen, or make a flat cut to indicate the base and an angled cut for the top; this will ensure that you’ll place the proper end in the rooting medium.
Use a knife to scrape off 1/2 inch of the bark on the base end, keeping at least one node that you’ll insert fully into the medium. Then, dip the base in rooting hormone. Plant it in a 50-50 blend of perlite and vermiculite or, ideally, 100 percent perlite. Avoid using potting soil enhanced with fertilizer, as it may burn young roots.
Place the cuttings in indirect sunlight, and set up a mini-greenhouse (to maintain a moist environment) by turning a clear container over the pot. You can also use a misting system. If possible, place the pot on top of a heating pad that maintains 75 to 80 degrees. Rooting will occur in 1 to 2 months. Transplant the rooted cuttings into quart-sized pots until you’re ready to plant them outdoors.
Choose a planting site carefully. In cooler areas, the best fruit yield requires the warmest possible location. Growers usually plant close to the south or southeast side of a building, preferably made of stone or brick, to reduce winter wind exposure and provide a microclimate.
Dig a planting hole three times larger than the plant — at least 2 to 3 feet in diameter and 1 to 2 feet deep. Improve the soil with a bag or two of manure, and mix it into the hole with a shovel before planting. Water the hole well before planting, and again after you’re finished.
A Wonderful Cultivar
The first pomegranates to grow in American soil were likely seedlings planted at Spanish missions after the mid-16th century. These seedlings eventually made their way to California. But they were mostly tossed aside for selected hybrids, such as ‘Wonderful,’ during early attempts to start a pomegranate industry in California.
One of the most commercially successful heirlooms grown today, ‘Wonderful’ defines the American pomegranate industry and holds a virtual monopoly over all other cultivars. Many of its minor competitors, such as ‘Early Wonderful’ and ‘Granada’, are actually its sports.
The precise details of the birth of ‘Wonderful’ remain obscure, but its first recorded appearance was at the nursery of fruit hybridizers J.T. and F.E. Bearss in Porterville, California. The Bearsses mounted a massive marketing campaign for their promising seedling. In 1894, they sent ‘Wonderful’ to anyone who agreed to promote it. The cultivar received endorsements from the American Pomological Society, the California Secretary to the State Board of Horticulture, and the Atlanta Exposition, which awarded it a gold medal. The cultivar’s value as a multinational brand name is thanks largely to the Los Angeles company POM Wonderful, which adopted the moniker in 2002.
The appeal of ‘Wonderful’ comes from a group of traits that rarely appear in a single cultivar — vigorous growth; dependable and heavy production; balanced sweet-tart flavor and aroma; medium-soft seeds with a relatively thick layer of flesh; high fruit-to-pith ratio; high-quality juice; a rind that resists splitting; and a long shelf life. Comparative studies also show it has among the highest seed weight and antioxidant activity of any pomegranate.
The main caveat about ‘Wonderful’ is that it requires extra winter care at Zone 8 or lower. Some trials have also found that other cultivars are better for humid areas of the South.
Levin Hybrids
For 40 years, Soviet botanist Gregory Levin led the creation of the largest collection of pomegranates in the world, with 1,117 different types. In addition to trekking through dangerous deserts and mountains in search of wild pomegranates, Levin hybridized the plants. Among the most prized of his hybrids are ‘Salavatski’ and ‘Parfianka.’
‘Salavatski’ has earned a reputation on the East Coast for flavor comparable to ‘Wonderful,’ and a high tolerance for humidity and cold. The cultivar can be grown next to a heat-absorbing wall at least as far north as Allentown, Pennsylvania (Zone 6a to 6b), and survive aboveground most winters without any extra protection. ‘Salavatski’ has also scored well in commercial trials in Florida and Georgia, and earned a perfect score in Levin’s taste tests.
‘Parfianka’ was Levin’s own favorite and received top marks in a U.S. Department of Agriculture study on cultivars with commercial potential. Study co-author John Preece believes that many people would prefer ‘Parfianka’ to ‘Wonderful’ because it has softer seeds and greater cold-hardiness.
Japanese Double-Flowered
All pomegranates are ornamental, but Japanese hybridists have placed a premium on flower form and color. Among their achievements are blooms shaped like roses, peonies, and dianthuses, and variegated forms in white, pink, red, and orange. Some of the following cultivars are being researched in California and Florida for use in the floral industry.
‘Haku Botan’ is the most vaunted, and bears white flowers as fully double as an old garden rose. Plus, it also has commercial potential, because it reliably produces bountiful fruit. Growers in the Northwest report success with this cultivar.
‘Ki Zakura’ is a showstopper with variegated orange flowers shaped like those of a carnation. The cultivar produces small, edible yellow fruit.
‘Toryu Shibori’ closely resembles a quartered rose, with apricot-colored flowers that develop into a large crop of fruit.
Double-flowered varieties are also widely grown at North American historical sites and are a possible link to an older colonial tradition on the East Coast.
Dwarf Cultivars
