JoAnne Skelly: Nuts! Northern Nevada climate unfriendly to pistachio trees
I love pistachios, so when I found out how nutritious they are, I was delighted. Pistachios contain fiber, essential vitamins and minerals like B6, thiamin, copper, phosphorus and potassium. In fact, two ounces of pistachio kernels have more potassium than a large banana. The fat content in pistachios is primarily monounsaturated, like olive oil and they are cholesterol-free (http://www.americanpistachios.org).
Realizing this, I wondered if I could grow pistachio nut trees (Pistacia vera). Pistachios thrive in an arid semi-desert climate with long, dry hot summers. Our climate meets those requirements. However, when I investigated further, I learned that “hot” means over 100 degrees. We rarely have long periods at or over 100 degrees. Then I discovered that winter lows can’t go below 15 degrees. In addition, strong spring winds during bloom will reduce pollination and fruit set.
I definitely won’t be able to grow pistachios here at home, not only because our site gets so cold (we have had negative 20 degrees for a week in a row), but the winds will definitely interfere with fruit set. We also rarely stay above 100 degrees at 5,000 feet elevation.
However, while there might be some protected sites with a warmer, less windy microclimate in Northern Nevada, on the whole, it would be extremely risky to plant pistachio nut trees. Besides, it takes a male and a female tree to produce fruit, so your investment in these trees is doubled. They don’t bear until they are five to eight years old. Then they only bear a heavy crop one year and very little the next year (biennial bearing). And we almost always have a late freeze that kills off blossoms. If that happened in the year a heavy crop was expected, you might not get any nuts for a few years. On the whole, we are unlikely to have nut success.
But wait, the ornamental Pistacia chinensis can grow in areas with winter lows averaging around 28 degrees, with occasional drops to zero degrees. This species doesn’t get fruit, but it has lovely red fall color. Since it grows to at least 30 feet, it is a nice-sized reliable shade tree. It also tolerates a variety of soils and watering regimes (Sunset Western Garden Book).
I, for one, don’t need any more shade trees and would much prefer that any future tree I plant bear fruit or nuts. Alas, the Pistacia vera is not for me.
JoAnne Skelly is Associate Professor & Extension Educator, Emerita at University of Nevada Cooperative Extension. She can be reached at firstname.lastname@example.org.