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Nobody would ever call the Mojave Desert a commercially important fruit production region, but home orchards are popular, and no wonder. During the spring, peaches and nectarines are gorgeous trees with wonderful flower displays. Even if they didn’t give some of the tastiest fruit ever, we’d probably still grow them.
Some fruit trees thrive in the intense summer we face in this challenging area. Among the surprising producers are pomegranates (Punica granata).
I think these are about the most beautiful trees or shrubs in any home landscape, although they are a bit spiky. In late spring, fruiting varieties produce lipstick red flowers, almost an inch and a half across, that develop into globe shaped fruits that ripen around Halloween. The fruit size varies with the different cultivars. There’re ornamentals that we grow only for their lovely flowers. In the Cooperative Extension pomegranate demonstration garden, we have 17 varieties, both ornamental and fruiting, both tree and shrub.
This plant’s been cultivated since at least the time of the Phoenicians over 3,000 years ago. It evolved in Iran or India. It was a symbol of fruitfulness on ancient Judean coins. In a number of Renaissance Madonna paintings, the infant holds a pomegranate as a symbol of eternal life. It’s important in herbal treatments for several health problems, and anyone who watches TV can hear commercials about its fabulous antioxidant properties.
Selective pruning can keep a tree to a manageable size, but even when it’s kept small, the plant’ll give an abundance of arils. These’re seeds wrapped in a luscious crimson pulp, surrounded by a hard skin. Some varieties have such small seeds that you’d hardly notice them. Some have pulp that’s nearly white.
As long as it isn’t exposed to freezing temperatures for long periods, growing in soil with good drainage, it’ll survive. Our climate is just about perfect for them.
Not only are they lovely, they’re long-lived – perhaps living a century or more.
One possible reason for its global popularity with humans is - this plant has only a small set of problems. We don’t see diseases on fruit or foliage.
Unfortunately, the conditions that make a healthy, happy plant sometimes also make a healthy, happy pest.
Even though human beings might try not to come out during the worst of the hot weather, that’s the time when some very annoying insects appear - in their legions. One is a major pest on our lovely pomegranate trees.
The big summer problem for our pomegranates is leaf-footed bug (Leptoglossis), which gets inside the fruit, and destroys it. An infestation isn’t just unsightly; it can ruin a crop. The adults are long-lived and very prolific. It’s possible for a single fruit to hold up to 100 nymphs, juveniles that look like small orange versions of their parents – a disgusting sight. They’re better known as a tomato pest, but apparently, pomegranates are their favorite.
As with so many problems, prevention is best: remove remaining fruit from previous years and clean up weeds where bugs can overwinter. Here in the Southwest, with our mild winters, this is critical. As soon as you see one, wash it off with a strong stream of water.
Despite our best efforts, bugs are attracted by their favorite foods. Few conventional pesticides are labeled for insect control on pomegranates. Pyrethrins are moderately effective, but they can harm bees and other pollinators. Some researchers had success using Neem oil, but this hasn’t been replicated widely. Beauveria bassiana’s a soil-borne fungus that kills many insect pests, and there’s some study using it on leaf-footed bugs. It may not be an option for this region, since it needs higher humidity. Still, anything’s worth exploring, especially when pomegranates show distress from these pests.
At extension, we’ve used Surround WP, a clay suspension. It doesn’t kill the bugs, but seems to confuse them. They don’t recognize the fruit.
Just like all the gardens at Extension, the demonstration pomegranate garden is free and open to the public. You’re more than welcome to come, learn and enjoy.
For KNPR’s Desert Bloom, this is Dr. Angela O’Callaghan of the University of Nevada Cooperative Extension.
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