New United States Hardiness Zone Map

A new United States Hardiness Zone Map was released today. It respresents some large changes here in Ohio. I was previously on the 5-6 line but now firmly 6(a). I’m not sure I’d trust it too much having seen -10 here not that long ago.

http://planthardiness.ars.usda.gov/PHZMWeb/

Drew Mc Farland
Granville, Ohio

8 comments for “New United States Hardiness Zone Map

  1. I too was going to share the map with the same comments. Maybe they think
    global warming will catch up with the map, but until then I will not trust
    this map any more than I did the previous one. This has us in 6a, but we
    get -20 and have had -32. Those who believe these maps lose their
    landscaping.

    Colleen NE Calif

  2. There are some strange hardiness zones on that map. I wonder if it is
    projected on future global warming.

    Drew, thanks for sending it.

    Clay

    Clay E. Higgins

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    240-632-0002

  3. I think it is indeed very strange. If you look at the state images, it
    says based on 1976-2005. As Mary Lou and I were commenting privately, that
    would include things like the Blizzard of 1978 where -22 or -23 was reached
    here. It’s an average of course, but there appears to be no city effect
    either.

    When I first saw it, it crossed my mind to wonder if it had been toyed with
    in some way. I don’t really think that, but one really doesn’t know what
    to think anymore!

  4. I would not trust this map either.
    when I 1st joined the ADS in the early 90s, we routinely experienced
    lows of -25 & one year I thought the local weather stations thermometer
    was broken as the high didn’t get above 0 degrees F for TWO full weeks!.
    Last year, at our new location in Cincinnati, around this time of the
    year, we observed -10 (F) first thing in the morning. These temps are
    reflected in the map at a 4B rating but using the current map look-up
    tool, it says we are in the 6A range area.

    We have some very old yellow double daffodils that were growing here
    when we moved. They already have buds above ground.
    various others are sending leaves above ground as well. I have 6 days of
    vacation time left which I’ll use to get the mulch ordered & put in
    place before they get too high.

    I need to tend to the seed box as well, to allow the 1st years seed
    plantings to come through more easily.

    Tom

  5. The new USDA map is not based on future temperatures based on any
    theory, but on actual temperatures measured over the past 30 years.
    Averages, of course, differ from absolute extremes. “Hardiness zones
    are based on the average annual extreme minimum temperature during a
    30-year period in the past.”

    It is true that globally, and on average, the last decade has
    included 9 of the hottest years on record.

    http://earthobservatory.nasa.gov/IOTD/view.php?id=76975&src=eoa-iotdhttp://earthobservatory.nasa.gov/IOTD/view.php?id=76975&src=eoa-iotd
    “Nine of the top ten warmest years in the modern meteorological
    record have occurred since the year 2000. Last year was another one
    of them, coming in at 9th warmest since 1880.”

    We are also accustomed to a certain predictability of
    weather. However, worldwide, weather appears to be increasing in
    variability, and extreme events are becoming more common, so the way
    one uses the new map will not be exactly the way one was able to use
    the old map, based as it was on less-variable weather conditions at a
    given location. But neither does the old map give an accurate
    picture of the current situation.

    http://planthardiness.ars.usda.gov/PHZMWeb/About.aspx There is some
    explanation at this link which also makes the point that hardiness is
    gained by a plant when temperatures drop slowly. A sudden cold snap
    in the autumn can be deadly to plants that would have endured the
    same temperatures easily in late winter after hardening. So there
    are many ways that the temperature, its extreme values, its duration,
    and its rate of change over a season can affect various plants.

    Melissa

    At 06:33 AM 1/29/2012, Tom wrote:

  6. There is another article, a statement signed by 16 prominent world climate
    scientists, in Friday’s Wall Street Journal (page A15) that reiterates the
    lack of warming data, and again alludes to the faulty computer models at the
    center of the 2009 scandal, models that show multiple warming years, but
    only after the data is subjected to unsubstantiated feedback (manipulation).
    “Alarmism over climate is of great benefit to many, providing government
    funding for academic research and a reason for government bureaucracies to
    grow. Alarmism also offers an excuse for governments to raise taxes,
    taxpayer-funded subsidies for businesses that know how to work the political
    system, and a lure for big donations to charitible foundations promising to
    save the planet.”

    _____

  7. Daniel:

    Yes, I know one of those signers. Some are scientists whose
    professional competence does not extend to climate issues, but is in
    biology. Their views are not supported by the overwhelming consensus
    view in the science community, nor by the data of many different
    sorts. They are individuals with strong personal opinions that do not
    accord with the accepted views other professionals have developed
    based on their own review of data.

    Sea Level is rising. Permafrost is melting. Arctic Sea Ice is
    greatly diminished in extent and thickness. Ranges of birds are
    shifting. Ranges of plants are shifting. We have satellite photos
    of areas in the arctic tundra that 30 years ago were barren and are
    now covered by shrubs. These are only a few of the types of data available.

    Science is a method and an art that derives a view of truth based on
    observation, and that ties observations together with theories based
    on physical laws. As new data become available, there are those who
    readily change their views to accommodate to it, and those who trail
    behind. In my view, those you mention fall into the latter group. I
    do not expect them to change. But a new generation whose lives are
    at stake will be more open minded, and the views you mention will
    pass into oblivion with our age cohort as the changes intensify.

    Melissa

    At 03:19 PM 1/29/2012, Daniel Bellinger wrote:

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