Don't get to excited about the Arbor Day zones. They base it upon temps for the last 20 years or so. Their trying to put as much global warming into them as possible. While I agree warming is happening, their view is much simplified and ignores a couple meteorological factors. Biggest being that in the north Atlantic there is a cycle called "North Atlantic Oscillation that lasts for decades at a time. I won't go into the details (you can look them up if you desire) other than there is a positive and a negative phase. The importance being positive has much milder winter's as whole, while negative tend to be much colder as a whole for the US. The NAO has been in predominately positive phase since (there have been two negative years) since the late 70's. Arbor Day base their zones on temps since about 1980 (look around on their cite and you can find this info). So they are probable somewhat skewed to the warm side IMHO. Assuming the NAO follows previous patterns it is due to switch back to a predominately negative phase sometime in the next several years. Resulting in colder longer winter temps, assuming everything behaves as it has in the past. Historically as much as a USDA zone colder than the rated USDA zone.

In short, I would still go by USDA at this time, as Arbor Days are likely skewed by the NAO. So personally I don't buy into Arbor Day zones just yet.

JMHO
Arktrees

We went over this issue already on some tree listservs before the new map came out.

The new zones are relevant, germane, and not dependent upon wishing the NAO changed temps in California or Montana. That is: there is copious corroborating evidence - earlier bloom times, earlier ice breakup, earlier bird nesting dates, northward species movements, etc. The evidence is there to justify the new map, regardless of whether or not you want to believe scientific findings.

Also, AFAICT there have been no journal articles published that 'correct' the zone changes.

Dan

hello, thank you for the replies to my ? on the hardiness zones, it was part of an earlier post on here about a Quercus Virginiana labeled zone 6 at a Fla Lowes. I guess it must have been a mistake on their part, (Lowes) and my tree will not make it here. I can get my money back but feel bad about the tree.I guess if it does survive it will be stressed and not grow well, I just love the tree after seeing it in its element, Fla.Thanks for any replies.

Whether or not that particular species has any potential in eastern USDA 6 the thing you always have to watch out for with commercial (and often other) hardiness zone assignments is them being based on misunderstood or misapplied zone definitions. The common mistake is to read the temperature ranges given for each zone (such as -10F to 0F for USDA 6) as indicating the coldest it gets there. This is incorrect, the temperature ranges the USDA gives to characterize each zone are based on

average

annual

minimum

temperatures

recorded at weather stations spread through each zone and not on record lows. So it sometimes gets below -10F in USDA 6 and so on. A plant genuinely hardy in a zone will have to be hardy to well below the temperature range associated with that zone.

Dan,
Frankly Chill. I said warming was real and relevant, however I have been spending time on climate sites. I have not been on any tree listservrs. Climate scientist are very concerned that when the NAO switches back to a negative phase, likely resulting in SOME cooling, just what the public perception will be. Much as El Nino warms the entire globe, and La Nina cools the entire globe. As your well aware, many will try to twist those results. The NAO effect is real, and result in just the sort of thing you site, as it also warms the climate. I tried qualified every statement I made trying not to overstate the scientific evidence. The amount of impact of the NAO is uncertain. I did fail to qualify the effect is much larger in the eastern North America and Europe, than for the rest of the world. It is almost certainly partly responsible for the observed warming, but in no way ALL. Warming is real, and certainly needs to be dealt with NOW. End of story. However I still believe the Arbor Day zones are skewed due to the time period and NAO phase. USDA is not correct, but I don't believe Arbor Day's are either. To use your own words, the scientific evidence is that NAO does have some effect (uncertain as to how much), whether you choose to believe the findings or not.

My whole intention was to caution about assuming too much. That is not meant as discounting warming, only that things are nearly as clear cut due to complication of the entire climate system. I personally will not be planting anything. I wouldn't plant anything I want to keep for decades if I am currently on the cold fringe of it cold hardiness based upon a map created during the warm phase of the NAO. Small stuff sure, but not a large tree etc that I want to keep for decades. At least not in eastern North American or Europe.

As previously stated,
JMHO (Just MY Humble Opinion)
Arktrees

I think I'll split the difference. Let's say (and I don't think its this extreme, yet) Global Warming has causes a 4 degree increase in St. Louis Missouri's average temp. So my 20 year average low goes from -8F to -4F. I don't think that even changes my zone!

Other factors like changing the gulf stream will change weather more for some locations but not the whole planet.

Lowe's sucks for figuring out what plant to sell where. Mine always has zone 7 plants for sale. Buying from the box stores is like buying from Auto Zone. You can save money but better know what you need because their guidance is of questionable quality.

I'm conservative so I believe in taking preventative measures to combat global warming. No ifs ands or buts but if there is even a 10% chance we're screwing up the world for our grandchildren we shouldn't take it. BUT, our detailed weather observations go back maybe 130 years. Maybe this drought for the Southwest is more normal than the previous "wet" period. The 20 year lows are interesting.

Poaky, You might try willow oak. They don't have those low hanging sprawling branches in maturity but they have the narrow leaves and look very similar to live oak up until that time. Unlike live oak, they are deciduous.

iforgotitsonevermind, thank you for the suggestion I have one willow oak in the yard in another area. I don,t know what to do with the Live oak though, if my friend in Fla owned property I,d give it to her.I have some English oak acorns coming in the mail that I got on ebay, I will put some of them in the area where the live oak is.I wish I could give the LO to a southern person, so it won,t be a waste.poaky1

Also, look around and see if there are evergreen oaks already in your area. Here in Knoxville (officially zone 6b) we have a number of large mature evergreen oaks scattered around the city. Many people around here may not even know about them, but they're here. Many are planted in protected areas (microclimates).

Stop by a respectable nursery and ask for their input or ask someone in a local tree society or garden club.

Oh, BTW, for anyone interested...the Arborday map errs on the conservative side for my area. They have us solidly in zone 7, but we are actually in a very low zone 8 if you apply the USDA formulation.

hello, brandon7 had suggested I check around my area to see if there are some evergreen oaks. I live in a small town,there are a few trees in town but they,re small flowering trees and the like. other than the live oak I,m not sure what other evergreen oaks are out there. The live oak is still out there in the yard, and it is in the best place it can be, above the little frost pockets about 45-50 feet from the brick house,which should throw off some heat. I guess I,m dreaming if I think that would help I,d have to pour a ton of cement to create a microclimate to keep the tree happy, it may be fine for a few years and one bad winter will kill it.Any suggestions for hardier evergreen oaks anyone? poaky1

It,s poaky again I searched the internet and the Quercus fusiformis is touted as the hardiest evergreen oak although it is supposed to grow very slow, anyone have one? I guess it can,t grow any slower than my beech.poaky1

I haven't reviewed this list at all, but maybe it will give you some ideas:

Here is a link that might be useful: Evergreen Species in the Quercus Genus

I'm not sure where you are at but Q. myrsinifolia is supposed to be hardier than Q. virginiana. Check out Q. acuta and Lithocarpus sp. as well.

The important thing to remember is that plant hardiness zone designations are only considered guidelines. There are all sorts of other factors that can influence a plant's ability to thrive in any given location, including summer temperatures and humidity, altitude, proximity to large bodies of water, soil conditions and amount of annual rainfall. And immediate microclimates.

I've been around GW long enough to be able to recall dozens, maybe hundreds, of posts from gardeners who are successfully growing plants - long term - well outside/below their specified cold hardiness zone. In some cases, plant hardiness information has been altered or extended because of similar experiences.

Since you already have the tree, it never hurts to try and see how well it does. If you are pushing the zonal envelop, I might want to hold the plant in a protected area over winter and plant in spring :-)

thank you for the ideas.I think I will just keep the Q. Virginiana where it is, the 3 other evergreens one person suggested I,ll look into also. I have the tree already in the ground generously mulched, a couple inches maybe 3, there is not much use to baby it and protect it much, I live in SW Pennsylvania, someone had asked about where I,m at it,s about 30 miles from Pittsburgh. I,m in a rural area and the tree is sheltered from the northern winds by a large shed.It,s at the highest point in the yard.Close, (50 ft) from the house(masonry)so it may warm the area(maybe)I will just see how that goes, I,m not sure about microclimates in my yard.I read in the older posts on here that someone in the state of Indiana has Q. Virginiana in their yard.I wonder how theirs is doing.The Q. Fusiformisalso mentioned by somone looks like a great tree but is supposed to grow very slowly and the zone given is zone 6 and I was told by someone on here that I should try to get a tree with more hardiness provenance. So in a nutshell I should give the tree I have a chance and see what happens.poaky1