Will, I think it's best to consider the needs of the roots and tops of the plant separately. The USDA zone rating is a rough geuss but as you know, with so many other factors coming into play as well (wind, wet soil, on and on...) Here's an interesting example from the same webpage you quoted from above: "Cedrus atlantica, brevifolia, and libani are all grafted onto Cedrus deodara, the least hardy of the three. There are several reasons for this choice. The hardiness is not a factor since the deodara root system in the ground is at least as hardy as any Cedrus cultivar above ground. Secondly, the root system is more fibrous and better developed than in the other species making it a much better choice for nursery use." In this example, the top is least hardy, but the roots are most hardy, and the species is the preferred understock. I geuss this all gets at your fourth question to illustrate that you cannot make a plant "more hardy" by choice of rootstock, unless the limiting factor is the hardiness of the roots (not the top) in the first place. I geuss others already made this point more concisely - just wanted to add my two cents and what I thought was an interesting and illuminating example. Alex

Thanks for the advice. I'll ask the vendor about pot size and potting-up history if applicable, and caliper. I haven't used pungens understock before but have heard about the problems with sharp needles. At the same time, I've also heard that some growers prefer them since think they form a more fibrous root system in the ground (compared to P. abies). But it seems like most people here think the sharp needles problem out-weighs any potential advantages. Is one or the other better suited to growth in clayey soil?

For next year they have 'Calvary' available in #3s or #20s (the #20s must be gigantic plants). Haven't seen that it is officially added to their product line yet. Newer material that they have added for next year are: Spruces: Picea pungens 'Golden Feathers' (got three of these in 4-5' size), Picea pungens 'Hermann Naue', Picea pungens 'Millbrook', Picea abies 'Gold Drift', Picea glauca 'Keji', Picea abies 'Blaze' (I think this is a smaller, fuller seedling of 'Rubra-Spicata' that has the same brilliant red new growth) Pines: Pinus strobus 'Stowe Pillar', Pinus strobus 'Mohr', Pinus bungeana 'Morris Arb. Witches Broom #46' Arborvitae: Thuja occidentalis 'Kunau', Thuja occidentalis 'Linwood #4', Thuja occidentalis 'Riverside #2' Several of them I can't find much info on. They also have a couple newer plants they are introducing but haven't given a proper name yet- one is a witch's broom from a Picea omorika 'Bruns' and the other is a seedling of the hybrid selection Picea x 'Ali'. Can tell the nursery business has improved dramatically compared to two years ago as they are sold out of an incredible amount of plant material.

Anna, I have two small golden spreaders, both doing well, but both are on firma rootstock. I have seen larger golden spreaders at local nurseries, but I'm unsure of their rootstock, and just because a local nursery stocks a plant doesn't mean it will thrive here. It's even conceivable that the golden spreaders could be grafted onto a rootstock other than nordmanniana (or firma). With firs here in Georgia, I would always know the rootstock before purchase. Having said all of that, if it's a pure Abies nordmanniana golden spreader, it should be able to survive in Atlanta, although I'd expect a higher failure rate than with firm rootstock. It's a beautiful plant, and if you have a bit of disposable cash and time to nurse it along, I'd say go for it.