Thursday, Sept. 24, 2009 | 2 a.m.
Dear Mr. Sun, why are there saguaro cactuses in Arizona but not in Nevada? They’re the desert. We’re the desert. Why no giant cowboy cacti here in Las Vegas?
Las Vegas would seem a nurturing environment for most any desert spectacle. Alas, the towering, iconic saguaro, which can grow to 60 feet and sprout dozens of upward reaching arms, isn’t suited to Southern Nevada.
Saguaros (pronounced suh-WAR-o) are native to the Sonoran Desert, which covers southern Arizona and parts of northern Mexico and southeastern California.
Experts say two factors keep the desert giants from expanding into the Mojave — temperature and rainfall. Las Vegas gets a few too many days below freezing for saguaros to thrive. Then there’s the rain, or lack of it.
Tucson, in the heart of the Sonoran Desert, averages about 12 inches of rain a year. That’s fairly wet for a desert and certainly wetter than Las Vegas, which saw less than 3 inches of precipitation last year.
For saguaros it’s also important when the rain falls. The cactuses are dormant in winter, so it’s summer precipitation that counts.
“Saguaros grow in the summertime when there is the hotter weather ... and the seeds get down in the ground and the summer monsoon rains are germinating the next generation,” said Doug Larson, horticulturist with the Arizona-Sonora Desert Museum.
July and August are the wettest months in the Sonoran Desert, averaging more than 2 inches of rain in some parts. Meanwhile, Las Vegas’ wettest months are from December through March.
That doesn’t mean a saguaro waking up in Las Vegas is doomed. A few lurk in landscaping around town and appear to be surviving.
Larson said their caretakers should be aware of the cactuses’ unique needs.
“Hopefully people in Las Vegas who have them in their landscapes will water them,” Larson said. “Once a month in the summer should suffice.”
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