Beam me to Planet Gore !
Posted on 06/11/2008 5:59:30 AM PDT by Diana in Wisconsin
Nancy Nedveck loves the colorful blooms that grow on agastache and penstemon, two plants that attract tiny hummingbirds. Some varieties of these plants used to be too fragile to grow in south-central Wisconsin, but now Nedveck is happy to be able to offer them among the endless rows of perennials on display at her nursery, south of Oregon.
Thanks to global warming, these and other less hardy plants are surviving and even thriving in this area, said Nedveck, who has owned the popular Flower Factory for 25 years.
"The change over the past 10 years has been gradual," she said, but has accelerated during the last five, as temperatures warm and the growing season lengthens.
An ornamental known as giant silver grass, for instance, would not have bloomed in Dane County in the past but now the longer growing season gives it time to produce its fluffy silver flowers. Japanese maples, flowering dogwood and hardy gloxinia also are now thriving.
What all this means to local gardeners is that the "zone" code on seed packets and planting guides may no longer be accurate. These often rely on a hardiness map put out by the U.S. Department of Agriculture that the government hasn't updated since 1990.
The map puts south-central Wisconsin mostly in Zone 4, but Nevdeck says the area is now more of a Zone 5.
The National Arbor Day Foundation, which just recently released its own zone map, agrees with Nevdeck.
"The map confirms that much of the United States has warmed in recent years," said Mark Derowitsch, public relations manager for the foundation.
But while the zone shift gives local gardeners new courage to experiment with plants they might have shied away from in the past, experts urge caution. Seasons are variable even during a warming climate trend -- as last winter proved -- and such factors as early freezes, snow cover and "micro-climates" in one's own backyard must also be factored into planting decisions.
A zone map, in other words, "is not the be-all and end-all," said David Ellis, director of communications for the American Horticultural Society. "The map is a tool to help gardeners select plants. You have to take into account cold hardiness, heat tolerance, rain levels and other factors that affect how plants thrive and survive."
The National Arbor Day Foundation's 2006 Hardiness Zone Map differs substantially from the 1990 map from the USDA. In the foundation's map, southern Wisconsin is now solidly in Zone 5 and northern Wisconsin is in Zone 4, each one zone higher than in the past. The central part of the state is a mix of the two.
Drawing on data from 5,000 weather stations around the United States, the zones are based on average annual low temperatures using 10-degree increments. Those increments are further divided into 5-degree A and B zones; plants in A zones are able to survive lower temperatures than those in B. The Zone 4 range is from -20 to -30 degrees Fahrenheit. Zone 5 is from -10 to -20 degrees.
Karen Johannsen, co-owner of Johannsen's Greenhouses, said many local gardeners have been successful with Zone 5 perennials that are a little less hardy than Zone 4 plants.
But she warned that there could always be problems with a bad winter.
"Even though it's been warmer, we still get a 20-below plunge just long enough to kill stuff," Johannsen said.
In some areas this winter, for instance, an ice layer under the snow smothered plants and other plants rotted under heavy snow cover, she said.
And because plants are blooming later in the season, they may not go dormant, leaving them vulnerable to winterkill when a cold snap does hit, Johannsen added.
Ellis of the American Horticultural Society said his organization recommends that gardeners visit their local botanical garden to see what is growing there.
"They are usually on the cutting edge as to what can survive, and many have trial gardens for borderline plants," Ellis said.
"Our overall recommendation is to experiment a little with plants that are less hardy than the traditional zones but not to make wholesale changes to the garden."
Jeff Epping, director of horticulture at Olbrich Botanical Gardens in Madison, said he uses hardiness maps as a general guideline.
"I don't use them as the bible because I have killed plants that supposedly are hardy according to the map and I have successfully grown other plants they say are not hardy for us here," said Epping, noting that some Japanese maples in the area did not survive this past harsh winter.
He said it would be reasonable to plant a zone up or zone down.
"If you are a gardener, have fun, and use the zones as a general guideline. But half the challenge is to grow things you're not supposed to," Epping said. "We have plants here that by the books shouldn't be here. But plants don't read books."
Local gardener Jane LaFlash, a member of the board of the Wisconsin Hardy Plant Society, grows hostas, ferns, geraniums, woodland wildflowers, small trees and shrubs in what she calls her "small, very urban and sheltered yard."
"I make the assumption that the nurseries are selling things that are hardy," she said. "They should only sell stuff that is hardy here."
LaFlash said every garden is different.
"You might have a little micro-climate in your yard, or a corner of your garden, and a few miles away there is a different situation."
Ann Munson, the Dane County UW-Extension master gardener, favors a conservative approach and says local gardeners "are in denial."
"They try to buy plants that are hardy for Zone 5. Some winters that works. This winter we lost a lot of things that have been hardy for years."
Evergreens, maples and such shrubs as nine bark, for instance, suffered damage.
People using Zone 5 plants should put them in sheltered locations out of winter wind and winter sun, Munson suggested. Zone 6 plants should probably be avoided, she added.
Several experts, including UW-Madison horticulture Professor Brent McCown, also warned that global warming would likely bring more extreme weather, including periods of heavy rain followed by drought. Also, new pests and plant diseases will move farther north.
"You can plant things you wouldn't have been able to, but the bad news is that the various pests and pathogens also are shifting with these hardiness zones," said John Williams, an assistant professor in the UW-Madison Department of Geography and the Center for Climatic Research.
He also noted that scientists are predicting more extensive zone changes in the future, depending on how much greenhouse gas spews into the atmosphere: "We can expect drastic changes of hardiness zones and the plants we grow and the natural landscape around us."
The hardy arctic plants here are in pain due to late spring and lack of summer, second year.
Aw shucks! Are you saying that the politics of globull warming hasn’t invaded the gardens of honest, patriotic Republican gardeners yet?
Brr! This is the coldest spring we’ve had in a long time. We’re getting the rain and cool weather we should have had in April and early May. I’m not complaining about the rain, because it means I don’t have to water, and because we’re not facing those catastrophic floods that other areas are. But still, this “warming” claim is ridiculous.
signing in from Georgia, where the temps area already hitting the high 90s and the drought is already intolerable. Not much grows well here, unless it is established. I don’t have any fruit trees, but my young maples and viburnium are suffering a bit.
Might as well forget about impatiens or begonias or other annuals. I’m trying out sedems, euphorbia in particular. Thank goodness for my daisies and daylillies.
And my hydrangeas, my favorite flower, are pitiful. They simply cannot bare the sweltering heat.
global warming?....maybe incidental....maybe transient.....but try telling my tomato plants that its June and they should be having buds by now.....
I’m staying in z6b even though winter is starting later in NJ with the ground not freezing until Jan. 1 now, and our low temps no worse than 5-10 deg. F most years (supposedly z7).
What I think separates z6 from z7 is the ground stays frozen in z6 and it doesn’t in z7, not more than the top couple inches for a few days, whereas mine is frozen deep for three months. Air temp is not so relevant.
And when your ground that freezes has a whole lot of clay in it, you can’t push zones too far.
I still lift cannas, salvias, agastaches, brugmansia, and rosemary and I’ve lost a lot that is hardy even to z5 in Western states. I’ve lost more z7 stuff than I can count, even with the best drainage I can provide and mulching.
My zone-pushing abstinence pledge was broken by a Hamelia patens (firebush) from Lowe’s. Why are they tempting me so far up north? It was for the hummingbirds you know.
Basically I pledge to make and break my pledge every year. :)
The temperature has risen 1/10th of a degree<<<<
See, there is proof of the global warming.........[said with a laugh].
The world must have tilted, as in NW Arizona, I am still having cool days and cold nights, which is all wrong for the normal.
Interesting thread, I will link it on the survival thread...
LOL, yes it is interesting and I have put a link up for it.
The lady in Oregon complains of the warming, but my sister in the Seattle area, complains of the late snow.
Don't worry.
We will be on your side when you are.
:-)
Diana, you probably already know, but fr those of you who don’t google “The year without a summer” It’s a real eye opener.
You wouldn’t believe the stuff I’m seeing this spring with this wet, cool weather!
Anthracnose and gall on Maple trees. NOTHING bothers Maple trees.
And bug damage beyond belief.
I’m selling lots of chemicals and organic solutions, though. That’s always good for our Bottom Line. :)
Oh, Brother. I was JUST kidding you!
I would’ve thought that a Fig Farmer would have a thicker skin!
See? I did it again. :)
The polar axis is regular in moving from past true.. and it moves incrementally. It has recently found a position. And because of this North Carolinians will now be able to grow orchards the like of which they've never before been able. And because of this all kinds of areas around the world should experiment with what they can grow, and might reduce crops (or move those north/south).
When I was kid in the San Francisco Bay Area -- every summer was predictably HOT. The years leading up to my move out South/east, I was actually wearing sweats at times during summer in the SF Bay Area. Changes in weather? Yep, I've seen 'em during my lifetime. Microclimates? I love 'em. But! This also means extremes in weather will happen in spurts until the entire cycle adjusts to new "true". It's not a calamity. It means to be aware, and make adjustments accordingly. It's evolution just evolving, again, and here are the so-called Most Earthy of the Earthies, the Liberals, screaming like chickens with their heads cut off, over natural rythyms of the Earth.
And tragically, must be said, until that synthesization occurs, there will be dramatic earth/weather events. We don't know enough about natural rythems to predict how this change will specific effect areas or microclimates; so much is contingent upon winds, mountains, rivers, tectonic plates, magma to surface, etc.
The article is quite right, tho - to experiment and see what will or may grow under these newer "terms". And to be aware this will also bring about newer insects, newer types of allergies, etc.
Liberals find evolution SCARY!
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