Interesting points Bboy, some of the big nursery sellers around here turned out to be friggin' weeds - like Norway maples, shrub honeysuckle, and Multiflora rose - they practically propagate themselves! Kind of like the fast food of the plant world. I think someone who advocates growing exclusively native plants is an extremist (although combining the word "nazi" with "native plant" is the other extreme). People like to grow exotics and that's not going to change. I take a moderate position and grow mostly natives but also grow non-invasive exotics like Lilacs, Daffodils, Peonies, etc. These are beautiful plants, easy to grow, and unlikely to take over the countryside any time soon. IMO it's well worth trying to control invasive species. What should people do, just roll over and let them spread rampantly until that's all that grows in the wild? It may not be possible to completely eradicate invasive plants that have become widespread in wild areas, but who knows - biological or other improved methods of control may be developed someday, that could eradicte or bring invasive species back into balance. Hopefully people will learn from experience and determine more efficient plans of attack for controlling invasive plants in the future.

cannot speak to heat tolerant conifers sad to say but i thought i would speak up for the surprising adaptability of Mexican conifers (Mexican oaks as well) to seemingly very different climates and localities. i have had gratifying success growing a number of species (likely mostly from areas with a summer rainfall maximum) here in the summer cool and dry (winter very wet) pacific north west (oregon coast)---including pinus montizumae, p. patula, p. pseudostrobus, p. estevezii,, cupressus montana, c. guadalupensis, and podocarpus matudae---.wonderful trees that once established seem to do well with little or no additional care.

"if this accurately represents tree hardiness, a number of trees deserve colder ratingscolor>" Let's look at which trees those might be.... From experience (three winters) I would say Picea breweriana is quite happy in my zone -- versus the Z6 designation above. Especially this year, the new shoots are extra long ! By contrast, I would probably move Pinus thunbergii from Z6 to Z7 -- no end of grief with this one (yet). My Taxus baccata 'Fastigiata Aurea' is doing a lot better, despite being rated the same Z6. That Z8 rating for Sciadopitys verticillata seems totally out of whack with what I've been told recently on this forum, although I have no experience with it myself. Z7 for Picea sitchensis seems a bit overblown too.... and probably likewise for Cephalotaxus harringtonia. And Pinus contorta rated Z7?! ....give me a break ! Not easy to find a reliable list, that's for sure.

I purchased it as P. Pungens 'baby blue' (you know the tags, "blue is cool blue is cool blue is cool blue is cool blue is cool"). It was only after a year or two that I noticed its branches were weeping. I think I planted it Nov 2014, but maybe Nov 2015. I do remember when purchasing it, it was different (I looked at every single one they had, probably over 200) but weeping never crossed my mind even though in thinking back I remember it looking about what it currently looks like. When I compared it to my 7 or so other P. Pungens 'baby blue', it was clearly different. I guess it would be considered a seedling with a mutation (or a mutated seedling?) ? The baby blue are grown from seed.