New Hardiness Map

Just scarfed this from the Ohio River Valley Forum. Thought it would make for interesting conversation here.

http://www.arborday.org/media/zones.cfm

Scott

In case you didn't notice the link to the additional map highlighting zone changes from the 1990 Hardiness Map, here is the link:

http://www.arborday.org/media/map_change.cfm

Scott

Oh boy! Shocked.

Most of the states of Kansas, Missouri, Illinois, Indiana, Ohio, Pennsylvania, New Jersey, and Connecticut are predominantely zone 6 where once they were predominantly zone 5. Given we've all been growing plants that aren't allegedly zone hardy where we garden microclimate or not, I think we knew this was coming.

I prefer the Sunset Zones, which will probably be updated soon too, because they try to compare some climatic differences from one area to another where the USDA basically compares nothing more than similar temps. Neither shows all the nuances to one's local area but they're both decent guides. One problem with the Sunset Zones is that you darn near need to buy their book unless you are familiar with their zones. Great way to get you to buy their book though.

http://www.sunset.com/sunset/garden/article/1,20633,845218,00.html

Is this because of global warming? I'm almost in zone 9 with this new map

sunset puts me in with a whole other zone, I am at the far end of 33 so puts with with a huge hunk of Oklahoma - a big other zone.. .. .. oh well

I knew the zone here was going to change soon - i buy and grow loads of zone 9 plants with no problem - on the new map I am still zone 8 but I push 9 with no problem (let me put it this way I have a lemon tree and tropical hibiscus both still green and growning with no problem. )

Wow--my tropical hibiscus (at least the one that I forgot to put in the greenhouse) is a shrivelled up brown thing right now from our week where we got into the low to mid 20's at night. Have you guys had a really mild winter so far? (like everyone in the country except us!)

Very mild for the last three winters... very mild... too mild and it is really nearer and nearer to the zone 9 every year - now they are planted right on the South wall with a little protection... but they are there.

Talk about global warming...

Global WARNING is more like it.

Almost entire state of Idaho and half of Wyoming have increased a zone. Am looking to move away from Denver(to many people) to the north/ northwest, but wasn't looking forward to colder/longer winters.

Yea? Zone 6! HA! HA! HA! Just 4 winters ago we had zone 4 temps right in South Eastern Michigan and there was plenty of damage to lots of zone 5 hardy plants in my garden not to mention a lot of marginal perenials were lost. I remember going over to David's garden and he had suffered damage to several of his Jap Maples. About every 7-10 years we get a wake up call. Not that I don't believe Global Warming is happening, but listing zone 6 for lower Michigan only shows how little the makers of this zone map understood of the seasonal weather in this reagon. I only guess that the other areas are as humorous. But, hey, what do I know, I only live here...

I do believe as Patrick suggests that calling where we live a solid zone 6 is probably wrong -- and that, from an "arbor day" group, who should be oriented as much to woody plants as anything else. In my old garden, even with very inconsistent and uneven snow cover, I could grow virtually any zone 6 herbaceous plant, and even some rated zone 7. That has not generally been true for woody plants, especially broadleaf evergreens and some conifers. Japanese Maples are often a problem here too though there are some varieties that are consistently hardy. That is because, as stated above, what these maps look at is range of LOWEST average winter temperatures. What they don't look at are many things -- duration of below freezing periods, duration of time ground is deeply frozen, liklihood of deep freezes occurring in spring well after spring warmups have occurred, etc. The reason JMs are a problem here has as much to do with the fact that deep killing freezes can occur in April and even early May well after temps have warmed, and early bud-breakers like JMs are already substantially in leaf -- long before the native maples have even 'thought' about breaking bud. We have had 2 winters in the past 10 where the low winter temp was down to -15F -- that temp is solidly in the zone 5 range. So even though I might be hopeful, with long term woody plants where those kind of once or twice a decade temperature ranges do matter, gardeners who play it safe need to be conservative.

Having said that, I am an envelope pusher. Nothing ventured, nothing gained. And here's hoping that my 15' Cedrus deodora 'Karl Fuchs' will make it through another winter with flying colors in a protected spot, just like it did the past 2. And I have a C. libanii v stenocoma that is now 18' tall, has been with me in 2 gardens over 8 years, and looks like it has settled in for the long haul. We'll see......

Zone 6 - Western Lake Erie -NO WAY! david5311 is right. The deep winter may not be bad but 9 degrees on April 9 is. Lost a wonderful magnolia that day with bark split. Tought me a lesson I will never forget. Many JM's all around the area bit the dust. It was a sad sad spring.

I know that a loose mulch ( balsam,spruce bows) are helpful for the perennial garden in keeping warm soil from waking the plants too early (in time for a late spring freeze). Will the same thing work for woodies and trees? Those in the area reducing sap to syrup looking for warm days and freezing nights for greatest sap run. We seem to get our greatest damage on conifers (burn, that is) when the sun stimulates the exposed part of the plant and the roots cannot keep the plant in enough water. Dwarf Alberta spruce burns quite easily unless protected with bows or burlap tied to south side. Thoughts appreciated? Ken