Fancy fruit: Yes, you can grow and harvest pomegranates in New Zealand
Pomegranates are popular among foodies, with the juice-filled arils from the red fruit often used as a garnish in fancy restaurants. Hailing from the region from Iran to northern India, they've been cultivated in the Mediterranean for centuries. The trees can be very long lived – some for more than 200 years.
Pomegranates (Punica granatum) are a small-growing, deciduous shrub or tree with narrow leaves and frilly red-orange flowers. The fruit are orange-sized, with a thick skin that protects the rich pink-red arils of sweet, juicy pulp containing the seeds.
Pomegranates require a long, hot summer for the fruit to ripen sufficiently and be sweet and juicy. It should ripen six to seven months after flowering, which inches into our cooler part of the year.
Research in Turkey has shown that pomegranates require 2800-3300 growing-degree days (GDDs). Statistics NZ advises that GDDs range from 400 in Invercargill in the coolest summers, through to 2600 in Whangarei in the warmest. Therefore, only during the warmest summers in the warmest regions will pomegranates have the possibility of their fruit ripening to full sweetness and juiciness.
Planting in the warmest spot in the garden against a heat-reflecting wall will assist fruit development, though. Growing in a tunnelhouse or glasshouse to increase the temperature in the later part of summer would also be beneficial.
Anyway, slightly immature fruit is still entirely edible – just not as sweet. And with climate change, we may even be able to grow full-flavoured juicy pomegranates in Southland in a few decades time!
Pomegranate trees are very hardy in a range of soil conditions, thriving in poor and heavy soil. And being deciduous, they're cold hardy to around -12°C.
Trees should be planted in a site sheltered from wind. The flowers require only 100-200 hours of winter chilling to form, which even the warmest of Northland winters would provide. Consistent soil moisture is necessary from flowering time through to harvest, so keep watered if rainfall isn't regular (irregular watering can result in split fruit).
Pruning & pests
Reaching around 3m in height, pomegranate trees can be grown as a large bush or trained with a clear trunk to form a tree shape. When young, the plants are a little bit scruffy with a multitude of leggy stems. These can be left if you're growing the plant as a bush, or trained up a bamboo cane to form a tree.
Once established, very little pruning is required, just the removal of any dead growth and suckers/sprouts from the base of the trunk (if growing as a tree). Pruning should be done in winter, as the fruit is mainly produced on new-season's growth.
Feed with a general fruit tree fertiliser several times each summer, and apply mulch around the base to help retain soil moisture.
Pomegranates aren't susceptible to any significant pests or diseases. In humid conditions, the skin of the fruit can crack but that's usually only cosmetic, so not a problem for the home gardener.
Pomegranates are self-fertile, meaning bees do the pollination work. It's not necessary to have more than one variety.
The most commonly available variety is 'Wonderful', which is commercially grown and has deep orange to red-coloured fruit with pink-red sweet and juicy arils.
'Eversweet' is available from Incredible Edibles – it has large, red fruit with clear arils and sweet juice. Originally from Afghanistan, it's cold hardy.
Don't be misled by the dwarf 'Nana' variety. It's more of an ornamental than an edible pomegranate, growing to just 1m with golf-ball-sized fruit. But it's an attractive shrub nonetheless.
Most pomegranate plants found for sale here are grown from cuttings. These are usually taken as hardwood cuttings (in winter) around 15-20cm long and about a pencil thickness.
Taking cuttings from suckers is usually quite successful. Dip in rooting hormone and poke into a tray of sand, perlite or light potting mix (basically anything except a heavy medium). Place in a warm environment, ideally with mist to keep the media moist. Roots should develop in four to six weeks. Transplant into a small pot and leave for a few months before repotting into a larger one. Plant out into the ground the following winter.
Pomegranate seeds germinate easily, but the resulting plants can be variable, so planting from seed isn't recommended.
Pomegranates usually start producing fruit two or three years after planting, though any really significant cropping begins after five years. In the first few years of growth, it can be a bit tricky to evaluate when the fruit is ready to pick until you develop an eye for judging maturity.
Pomegranates stop ripening once picked, but can become overripe on the tree, splitting and losing flavour. Size rather than colour determines the optimal harvest time, as colour can vary by variety from light orange to deep red. Look for fruit that's the size of an orange. Tap it and listen for a metallic sound, which indicates it's ripe. Never pull the fruit off the tree – use snips or secateurs to cut the thick stems.
Pomegranates can be stored for several months in the fridge, so if you're lucky enough to "suffer" a glut, you don't need to worry about the fruit going off before you can use it.
Eating & drinking
Each pomegranate contains between 500 and 1000 seeds (or more correctly, the pink-red orbs that contain the seeds), which can be used in a variety of sweet and savoury dishes. These arils are most easily removed from the tough white membrane by cutting the fruit in half and plunging it into a bowl of water. Scoop out the arils underwater and they'll rise to the top, leaving the membrane behind.
Try the arils in Moroccan-style couscous dishes, tabbouleh or rice salads. They go beautifully with ingredients such as orange zest, pistachios, almonds, sultanas, coriander and mint.
Use them to garnish your porridge, yoghurt or fruit salad for breakfast, or make your champagne extra fancy by adding pomegranate juice and a few whole seeds.
- NZ Gardener