Pomegranates for Now
Anyone interested in growing pomegranates is likely to discover that, while it is an ancient crop, it has not been widely studied in a systematic manner, an assessment that applies to cultural practices. The following is a summary of cultural information where there appears to be a reasonable and consistent foundation for the information.
Climate, soils, water quality, irrigation. The pomegranate plant is adaptive to a wide range of environmental and soil conditions, but is usually described as requiring a long, hot, dry season to crop properly. There are mixed reviews about its tolerance to salinity and calcareous soils indicating the need for further investigation. The plant is very cold hardy, but is not tolerant of wet conditions. It is responsive to irrigation as a recommended practice, perhaps with water not containing more than 2,000 ppm salt. However, plants in Israel have been irrigated with 4,000 to 6,000 ppm saline water with effects on vegetative growth but without significant injury to the plant.
Fertilization. There are few reports on formal fertilization studies, but supplying the usual essential elements apparently improves commercial performance. In Israel, Spain, India, and other regions, pomegranates are fertigated while in other places the plants are supplied with dry fertilizers. Some attempts have been made to establish leaf nutrient standards through research and some data have been developed privately, e.g., in California. Some evidence suggests that careful attention to certain nutrients can affect aril weight and fruit size without altering juice quality.
Propagation, orchard design, tree training. Pomegranates are readily propagated from stem cuttings of various size and age. They root easily with application of commercial hormone products and placement in a mist bed. They can also root when placed directly into orchard soil. Pomegranates can be propagated from seed. They have a relatively short juvenile period and can begin flowering in one year, but more typically after 2 or 3 years.
Good light interception is considered essential for cropping and fruit development. Thus, plants are usually widely spaced, ca. 10-12 x 20 ft. and trained to a form that minimizes the willowy young branches that bend under the weight of fruit. The plants are often trained to one to three trunks with an open vase canopy. In some instances, a single trunk is formed and three main branches diverge 1 or 2 ft from the ground to form the open vase.
Pests and diseases. Reviews of pomegranate culture have long lists of pests and diseases that include various insects, fungi, and bacteria. Among the insects, aphids appear to be common to most regions where pomegranates are grown especially among young plants at the propagation stage. Other insect pests are some of those common to citrus in Florida like mealy bugs, thrips, and various mites, but pomegranates are not listed as a significant host for Med fly (Thomas et al., 2010). Less information appears to be known about the Caribfly which has been found in much of peninsula Florida infesting guava and other soft fruits and occasionally citrus. In one study conducted only in the Miami area without any observation on seasonality of infestation, pomegranate was listed as a host of this pest (see Swanson and Baranowski and the DPI publication). Root knot nematode, Meloidogyne incognita, has been reported to be a serious pest.
The more serious problems are diseases caused by fungi and bacteria. Among these are leaf spotting, that can lead to leaf drop, caused by Cercospora punicae fruit blemishes also caused by Cercospora sp. and fruit decay that renders fruit inedible. The bacterial genera Botrysphaeria and Alternaria along with others are implicated as sources of fruit rot problems.