Washingtonian Gardeners Miss Global Warming

For some Washington-area gardeners, paradise lost

Last fall, Bo Barefoot said a quiet goodbye to his beloved Mexican fan palm and waited for the winter gods to take it. The palm tree had grown so large in his front yard in Glen Echo Heights, Md., that he could no longer afford to protect it against the impending freeze. The gods came, and they were greedy.

In addition to killing off the 26-foot palm tree, they took a rare yucca and, possibly, clumps of Japanese bananas that had spread 12 feet wide. Since January 2014, Barefoot also has lost four tall windmill palms and a mature, two-story Bismarckia palm that together had given his suburban yard a flavor of paradise.

“The last two winters have changed everything for me,” he said, looking glumly at the brown earth of his once lush garden. “I have had these plants for years.”
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Then came the winter before last, when the temperature dipped to 6 degrees at Reagan National Airport and minus-2 at Dulles International Airport. This past winter, it dropped to 5 at National and minus-4 at Dulles.

Beyond the numbers, the winters featured prolonged periods of intense cold and excessive snowfall.

The first frigid winter in years left gardeners demoralized, horticulturists say, and the second one has reinforced their view that the beach party that began in the late 1990s is over. The Agriculture Department’s plant-hardiness map puts the District in the colder half of Zone 7, with winter extreme low temperatures averaging 0 to 5 degrees. But the warm years convinced many they were in a Carolinian Zone 8 (with lows bottoming out between 10 and 20), a perception borne out by their ability to grow gardenias, hardier palms, perennials from Mexico and eucalyptus trees.

Yes, it was a pair of long, cold winters here, and we lost a few things that normally survive.  Our Rosemary bushes got clobbered last winter, and the perennial Verbena turned out not to be. One of our Butterfly Bushes (the yellow one that doesn't get quite as many butterflies, is barely clinging to life. It may or may not make it. However, all our natives are doing just fine, thanks, so whatever global warming that has occurred hasn't shoved them out of their ranges.