Pomegranate trees (Punica granatum) grow well across most of continental Australia, as long as sunlight is plentiful and the soil well-drained. Melbourne, Victoria, enjoys a long, hot summer--perfect for pomegranate flowering and fruit set. Even though deciduous in cold, turning its leaves yellow, pomegranates are hardy in Melbourne's mild, wet winters. Based on a map by the Australia National Botanic Gardens, greater Melbourne spans across U.S. Department of Agriculture hardiness zone 9/10--perfect for pomegranate culture.
Purdue University comments that pomegranates are long-lived plants. Older plants even in Melbourne easily attain a mature height of 20 to 25 feet. If lowest branches are pruned away, the pomegranate looks like a traditional small shade tree with one trunk. Burke's Backyard lists that in cultivation in Australia, pomegranates typically are erect, multi-stemmed shrubs about 12 feet tall.
Since the pomegranate tree is both freeze and drought tolerant, occasional winter frosts and long summer droughts across Victoria won't harm it. It tolerates winds, but when soils are dry and winds bombard it, it may not develop as many fruits or retain as many leaves. To produce fruits that ripen, plant a pomegranate so it receives at least eight hours of direct sunlight daily--too much shade reduces flowering and the heat necessary for fruit development. In Melbourne, a northern or western sun exposure is ideal.
Pomegranates grow in any well-drained soil. Near the coast in sandy soils, addition of organic matter will help the soil retain moisture vital to get the fruits to reach maturity. Even in the compacted loams in highly urbanized areas of central Melbourne, pomegranate survives well. If clay soils abound, add organic matter to improve water drainage and avoid low-lying sites.
In southeast Australia's cool and rainy winter, do not worry about irrigating the established pomegranate tree. Once flowers appear in late spring, monitor the soil and irrigate to keep the soil moist. Lack of moisture in the hot summer diminishes flowering and retards the growth and ripening of the fruits. In addition, a well-balanced granular fertilizer or monthly liquid fertilizer feeding alongside watering promotes more flowering and robust fruit set.
Pomegranates bloom on the current year's new growth. To increase branches that bloom and potentially yield fruits, lightly prune the plant in late winter. The pomegranate's response is to produce more branches in spring. Wear gloves when pruning, as occasional thorns occur on branches. Prune away any dead or hazardous branches, like those that block a sidewalk or a vehicle's line-of-sight any time of year.
Both fruiting and non-fruiting (ornamental) varieties of pomegranate exist and are sold in Australian plant nurseries. For tasty fruits, grow "Ben Hur" (which was developed in Australia), or "Nana," "Gulosha Azerbaijan," "Gulosha Rosavaya," "Elche" or "Wonderful." If possible, sample the fruits of the variety you wish to purchase to make sure it's a flavor and size you desire. Decorative flowering varieties include "Nana Plena" and "Legrelliae."