New Hardiness Zones

While the calendar tells me it’s spring, winter here in New England isn’t about to be ushered out that easily. For the most part, I have no business complaining. We had an easy winter. It was almost a non-event, in fact, up until February when winter half-heartedly tried to dip below zero a couple nights in a row and we finally had a bit of snow. Still, the nights are “cold”, dipping down into the 20’s, so while it won’t be safe to plant anything outside until mid to late May. That’s okay. Truthfully, I’m not much of a gardener. And my master-gardener father-in-law has evaluated our New England soil as “worthless without 10 good years of composting” so whatever I plant, I have to recognize limitations. Then, of course, there’s Chuckie, our resident woodchuck, to take into consideration. He was the only one who ended up benefiting from my last bout of spring planting-fever, making a buffet dinner out of 18 or so heirloom tomato plant. Fencing stood in his way, while our 65-pound standard poodle gave chase, neither giving him pause.

Still, I’m dreaming about Goji berries and Stevia gracing my hillside. I got the idea from a mailing this morning from the Mt. Timpanogos Nursery located just over the mountain ridge from our former home in Utah. “Timp”, as the locals called it, was invaluable for visual navigation of Utah County visible night or day from any valley location. And talk about beautiful – once you escaped the heat of the high-desert floor, hiking and enjoying the beauty of Timp, it was hard to come down from its quacking aspen, bubbling mountain stream, wildflower covered slopes. But I digress, lost for a moment of giving thanks for having had the experience of living close to such amazing beauty.

The Goji potted berry plants as well as Stevia, require Zone 5. I guess it’s been awhile since I’ve check hardiness maps because right in the middle of a good whining event, my husband informed me we are a Zone 5. Since when? Well, since new “hardiness zone maps”: referred to by my friend, Suzanne, were issued. Seems there’s been a lot of warming going on since 1990, the last time the hardiness zone maps were revamped. You may see the maps for yourself at The National Arbor Day Foundation. They even offer an animated version which gives me pause there might be something to the global warming frenzy. Then again, the glaciers have been melting for many thousands of years….



Hardiness Zone Map reflects warmer climate

Latest hardiness zones, based on most current temperature data available, suggest up-to-date choices for best trees to plant

Nebraska City, Neb. – Much of the United States has been warmer in recent years, and that affects which trees are right for planting.

Based on the latest comprehensive weather station data, The National Arbor Day Foundation has just released a new 2006 Hardiness Zone Map which separates the country into ten different temperature zones to help people select the right trees to plant where they live.

The new map reflects that many areas have become warmer since 1990 when the last USDA hardiness zone map was published. Significant portions of many states have shifted at least one full hardiness zone. Much of Illinois, Indiana, and Ohio, for example, have shifted from Zone 5 to a warmer Zone 6. Some areas around the country have even warmed two full zones.

In response to requests for up-to-date information, the Arbor Day Foundation developed the new zones based on the most recent 15 years’ data available from the National Oceanic and Atmospheric Administration’s 5,000 National Climatic Data Center cooperative stations across the United States. Hardiness zones are based on average annual low temperatures using 10 degree increments. For example, the average low temperature in zone 3 is -40 to -30 degrees Fahrenheit, while the average low temperature in zone 10 is +30 to +40 degrees Fahrenheit.

The new 2006 Hardiness Zone Map is consistent with the consensus of climate scientists that global warming is underway. Tree planting is among the positive actions that people can take to reverse the trend. Tree planters across the nation can go to, click on the Hardiness Zone link, and enter their zip code to determine their hardiness zone.

“The Arbor Day Foundation supports tree planting throughout America,” says Foundation President John Rosenow. “Providing the hardiness zone for individual zip codes at is an important part of that goal, by giving tree planters the most up-to-date and useable data available.”

“Of course existing trees should continue to be cared for,” said Woody Nelson from the Arbor Day Foundation. “Certain species may be more vulnerable to stress with the current warmer climate, but they will continue to provide environmental and economic benefits as they grow. It’s just a good idea to consider more tree species diversity for the future.”

Planting trees helps counteract global warming.

Trees counteract global warming in multiple ways. Atmospheric carbon dioxide is the leading contributor to global warming, and as trees grow they remove CO2 from the atmosphere, storing the carbon and releasing oxygen. A single tree can remove more than a ton of CO2 over its lifetime. Also, shade provided by trees reduces summer air conditioning needs. According to the USDA, the cooling effect of a healthy tree is equal to 10 room-size air-conditioners operating 20 hours a day. Trees reduce the “heat-island” effect in urban areas, where summer temperatures are generally warmer than the surrounding countryside. According to the U.S. Forest Service, 50 million strategically placed shade trees could eliminate the need for seven 100-megawatt power plants. Additionally, trees around homes and in cities slow cold winter winds, reducing the need for winter heating. This relief on fuel consumption for heating and cooling helps reduce CO2 emissions from burning fossil fuels.

Detailed information about which trees are best for planting throughout the country, the value of trees, and the latest warmer hardiness zones can be found at

The National Arbor Day Foundation is a nonprofit organization of nearly one million members, with a mission to inspire people to plant, nurture, and celebrate trees.


You can download the new Hardiness Zone Map at There is also a map that shows which regions have warmed and an animated graphic that shows hardiness zone changes since 1990.

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