New Hardiness Zone Map

With global warming (or whatever is going on), the National Arbor Day Foundation has completed and published a new Plant Hardiness Zone map. It's "good news" for many as a major part of the country has been upped at least one full hardiness zone! Check out your location at http://www.arborday.org/treeinfo/zonelookup.cfm (Note: Add /treeinfo/zonelookup.cfm to the address to get right to the map and locator. VERY interesting).

Arbor Day actually published their updated map in 2006...the USDA has yet to follow suit with an update to their map but I think I heard a rumor that they were considering doing an update. I can't remember where I heard that though.

According the the AHS, they are working on it.

It'll be interesting to see if the USDA comes up with a similar map. Some of the changes are quite dramatic! Did victorgardener find a proposed publishing date?

No date yet. I have to say that I don't put much faith in the Arbor Day one. It has my region the same as LI, and they are around 10 degrees warmer. My region may be borderline 7 now but LI needs to be bumped up.

The hardiness zone is, after all, what the thermometer actually says. I find that maximum low winter temps, while important, are not as much of a problem as a zone where the spring temps can go from an extended period of low 60's to 19 in a twenty-four hour period. Like here in NW Ohio last Easter. That was awful. Lots of damage. Where is the map or hardiness rating for that?!

True. Should be a craziness rating for that.

Everyone sure has added to a great discussion of zones! I think what some have pointed out makes sense, that it's not the occasional low temperatures, but long streaks of cold temps that do "permanent" damage. For instance, I've got some azaleas that are bud-hardy to 0º (plants hardy to 10 below zero). For the past three years, we've had a few winter nights below zero, but they've still bloomed well the next spring. In cold winters they lose more foliage, but they rebound the next year fine.
Down the road, there's a beautiful blue atlas cedar that has been growing for almost ten years and has reached over 12 feet. It's made it here in what is supposed to be Zone 5b through occasional winter temps well below zero and shouldn't be hardy here at all, but is! And it's growing right out in the open, not in a microclimate. This area in central Indiana is seeing other plants surviving now that have never made it for more than a year or two, if that: crepe myrtles, nandina, vinca major for instance. Also, some half-hardy perennials that normally would freeze out are not, such as Verbena bonariensis (zone 7) and snapdragons which die to the ground, but come back from the roots, not by reseeding. Only fifteen years ago, one never saw these plants make it through the winter! I guess the next few years will tell one way or another. I really look forward to a new USDA map, if they plan to update it. Meanwhile, many of us will keep trying to stretch the envelope of what we can plant. (Oh yeah, kudzu vines have made an appearance in central Indiana, too! Now that's really an unwelcome southern pest we never thought we'd have to deal with!)

They have our area in Kalispell MT correct. But none of the local nurseries think it is true. They don't want to have to replace trees by encouraging us. I buy them anyway in Seattle and bring them to Montana. We always have the -20 to -25 F but not this year so far. It usually is only a couple of days.

It's a comparatively balmy 14 above here today. However we have sustained 20 mph winds with gusts to 60! My neighbors' aluminum fascia blew off the front of his house last night and wrapped itself around my Miata! My new 12' Chamaecyparis nootkatensis 'pendula' seems to handling things just fine though much to my relief. It is staked, as it was just planted April 4th. Had to stake because it gets the full brunt of the prevailing westerly winds. I'll leave them on until spring storms have passed in June and then it should be fine.

Ya know Soferdig adhering to your zone would translate to fewer plant selections. I have several zone 6's in this zone 5. That's what oak leaf mulch cages are for. Now I understand that I am a true zone 6? Well see. Maybe.

I have several zone 6 in my garden and due to mild winters for 10 years I still have them. Though I have lost many other zone 6 plants in the past.

Wow those maps are unreal, especially the ones showing the changes. We are having more and more southern pests show up here in southern PA. (The map says I could now be in 7 - was 6b).

Maybe my rosemary will be able to grow real big. When you think about it gardeners and farmers are the first people who'll have to adapt quickly and who will notice the changes.

We are cutting edge, people!

Since it dropped 25 degrees in an hour here last night and lord knows how many total but my front door was frozen shut this morning, after being 65 yesterday. Not to mention a comment by my wife that this is the kind of weather that would have killed pioneers. I am reminded of the Winter of Deep Snow.

In the years leading up the Winter of Deep Snow, Illinois was considered a bit of a paraside. warm long summers, deep rich soil. But it was all a cruel trick mother nature was playing upon the settlers. By 1831 cotton was being planted, and expected to be the major crop of Illinois. Then came the Winter of Deep Snow. On December 20, 1830
a light rain began to fall, on Christmas Eve it changed to snow dumping 6 inches over most of the state. Tempetures fell and the snow kept coming.

Later one of the settlers recalled..

"For weeks, certainly for not less that two weeks, the mercury in the thermometer tube was not, on any one morning, higher that 12 degrees below zero. The wind was a steady, fierce gale from the northwest, day and night. The air was filled with flying snow, which blinded the eyes and almost stopped the breath of anyone who attempted to face it. No man could, for any considerable length of time, make his way on foot against it."

Today most have forgotten the Winter of Deep Snow even in Illinois. Its mark is still felt upon the land, Southern Illinois helped feed the rest of the state after the cold winter lasted too long and the next came before the crops were ready. Today some people passing through might take a moment to ponder why region is called Little Egypt, but most don't.

Anyway as look out over my yard and wish I was zone 7 or even 6, I am reminded of the Winter of Deep Snow.. and how foolishly a people let a decade of above average and mild winters.. lead them down a dangerous path.

With that said.. I am in TOTAL Zone denial, and aways seem to be trying to push the boundries of common sense. My wife claims I am trying to bring the South of my boyhood to our backyard.

This message was edited Jan 30, 2008 4:05 PM

It wasn't that long ago (1994) that the thermometer read -37ºF (-38.3ºC) in Shelby County, KY.

Even for one night, that's going to extinguish most people's idea of what zone 7 might allow. A lot of plants here wished that there had been more than the foot of snow cover that happened to be present.

I'm just hoping I'll still have some trees around by Friday . . .

Isn't this all so-o-o interesting!? It remains to be seen if this warming trend is going to last our lifetime, being "global warming", or if it's just a lull in the normal run of things. I too remember the record cold one January in the late 80s when the temp here in central Indiana hit a record -37º! That's the fun of gardening, for sure. Meanwhile, it's exciting to be able to grow some things that never survived before, even if it's just for a few years. I'm not expecting to make my little part of Indiana a tropical paradise, though! I don't want to LOSE those plants that wouldn't survive a drastically warmer climate. What would we do without lilacs?!

jfchapin:

Grow more viburnums!

Resin:

Batten down the hatches -- those northwesterlies look pretty fierce behind the isobars.

Resin as much as I respect you I cannot feel sad. For we have to battle each winter with the artic blast. Survive my friend.

Winds here yesterday were a sustained 30 mph. Gusts to 65. Tractor trailers loaded on flatbed rail cars blew off. Some located near the shore sailed into Lake Erie. The entire community is trying to reunite refuse cans with their owners. The neighbor's aluminunm fascia strip from the front of his house blew off sometine during the night and wrapped around my Miata in the driveway. Surprisingly few scratches. Best of all, no wind damage to any of our trees. Tonight and into early tomorrow were are supposed to get 6-9 in snow. This winter so far has been anything but dull.