Around here, where there are some individuals over 100' tall, a number of them burned in 1990 - the coldest winter in 30 years. In neighborhoods in bigger, older metropolitan areas near salt water this cold consisted of 2F-12F.

Cedar-of-Lebanon is rare here, the bulk of the true cedars being Atlas and Himalayan cedars. These are quite common.

Certain cultivars of Cedrus deodara, originating in the western Himalaya are much hardier than usual.

I have had this Cedrus deodara for about 4 years.

It is just over 6 feet tall and survived last winter which was brutal with many single digit (Fahrenheit) nights and days. There are a small minority of references which will give a zone 6 with most (almost all) saying it is a zone 7. This one has added no winter protection, but it is somewhat sheltered by large pines.

It is in a sunken area which may help...or hurt as cold obviously sinks. It has shown no ill effects from the cold and snow. Some Spring it may turn brown; in the meantime I will simply enjoy it. A favorite.

Jon

Since when you include the hardiest cultivars the minimum temperature range tolerated expands significantly it clearly is not possible to assign a single hardiness zone to the entire species with any serious accuracy. However, it is possible that there is a zone that most individuals are hardy to, apart from exceptional forms. This would probably not be as low as USDA 6 or 7 because of the numbers of them that burned here in USDA 8 in 1990.

It is probably, to a large extent a matter of how high (or low) an altitude the original seed source grew at in the native habitat. Or perhaps variation within closely related seedlings is possible, as occurs with gums (eucalypts), where seedlings coming out of the same pods appear to have 10F or more differences in cold tolerance.

I think it would be foolish to use a non-hardiness selected variety anywhere north of zn 8, though you could get away with it for years or decades.
Who wants a big brown dead looking tree after a cold winter, even if it can partly revive?

Jonny if you bought it locally, it seems very likely it was already one of the hardier clones, whether or not it was labeled as such.
Besides, I don't think New England had a truly cold winter. Yes it might have seemed cold compared to other recent winters, but nothing like 94, 85, 78 etc.

It was bought locally. David. It was something not normally in this nursery and seemed to be a late in the year special. It wasn't in good condition (severely pot bound)

For the above reason, I don't think it is possible to assume it it was hardy in this zone or not. Yes New England is relatively mild, but a couple of weeks of single digit temperatures cannot be considered anything but cold. The winter of 2012 to 2013 was not mild by any standard. The near record snowfall no doubt helped.

It is in an area where it would be easy to fell it if it doesn't survive (no structures nearby and an open area so it will not 'catch up' in other trees This is probably a unique situation. It works for me and I am hopeful it will last.

Jon

I'm originally from the Cleveland, Ohio area and I cant speak specifically for all Cedrus deodara but I know some of the hardier varieties such as Karl Fuchs, Eisregen, Polar Winter, Kashmir, etc have came through the winter of 08-09 when temperatures went down to -10F/-23C and perhaps colder in rural areas. I had a Gold Cone that came through with about 50% burn, but total regrowth by May. I also saw many, many, many Cedrus atlanticas that came through (some with burn, some without burn). I also know of the Cedrus deodara at Gees in Michigan that came through -20F/-28C and are still alive and doing well. Seems most should be hardy in zone 7.

If you consider a large (monumental, in the right climate) tree burning being "hardy". And what happens when there's a winter that is colder than one that merely burned the leaves? If a big tree dies during the cold somebody has to deal with the carcass.

Out here one of the common names given for Cedrus deodara is California Christmas tree. Where you start to see them all over the place is when you enter the milder climate of the Pacific Slope, all the way down to southern California. Any tree that has multiple individuals go brown in a 30 year Seattle winter is not going to be a solid Zone 7 item.