They are pretty much universally rated as hardy down through zone 6.

True, but there's a difference between zn 6 in OK or KS and in MI. I don't think these trees are common at all north of the upper South, and there's probably a good reason for that. Maybe they don't grow vigorously if the summers aren't hot enough?

The question of whether to consume a tree from a bigbox aside, that plant won't grow north of southern KY. Sunset Nat'l Garden Book is what you want to look at for the best climate zone descriptions (45 different climates). Which brings us back to consuming trees from a bigbox.

"True, but there's a difference between zn 6 in OK or KS and in MI."

My point was that the "zone 6" part is not the problem.

Brandon - good point, I should've said "Seems highly doubtful to me that it would be hardy in zone 6 in Ohio or Michigan".

After some more searching, I see that it apparently grows at the Cincinnati Zoo (photo), but Cincy is definitely a zone warmer than Toledo.

Also this publication http://arnoldia.arboretum.harvard.edu/pdf/articles/1978-38-5-new-trees-for-urban-landscapes.pdf says,“Michael Dirr has observed one plant fifteen to twenty years old growing in a home landscape in Champaign-Urbana, Illinois. The plant is 15 feet tall and is protected from the sweeping west winds by a house. While the plant hasn’t grown well, it has survived temperatures of -20°F during the winter of 1976-77.”

That's not a bad looking tree. I'd thought they were known for turning orange, not yellow.

The primary source linked above says one was undamaged at -15F in the 1977 winter at Morris Arboretum.

Here is what the RBGE multisite search finds in the US:1
hits returned from the Living collection of the Royal Botanic Garden Edinburgh
1 hit(s) matching pistacia from The Arnold Arboretum of Harvard University

0 hit(s) matching pistacia from The Holden Arboretum
1 hit(s) matching pistacia from The New York
Botanical Garden

4 hit(s) matching pistacia from Denver Botanic Gardens

0 hit(s) matching pistacia from Montgomery Botanical Center
0 hit(s) matching pistacia from Montgomery - Cycads
3 hit(s) matching pistacia from The George Safford Torrey Herbarium (CONN)

0 hit(s) matching pistacia from Brookside Gardens
0 hit(s) matching pistacia from the Betty Ford Alpine Gardens
0 hit(s) matching pistacia from The Botanic Garden of Smith College
0 hit(s) matching from The Scott Arboretum of Swarthmore College
1 hit(s) matching pistacia from Longwood Gardens

1 hit(s) matching pistacia from Niagara Parks Botanical Gardens and School of Horticulture

I'm unaware of any Chinese pistache at the Denver Botanic Gardens. Nevertheless, onesies or twosies surviving in protected microclimates aside, Lowes/BigBox have a universal palette, and often don't discriminate about what they carry in the nursery. We get rhododendron in Lowes' nurseries here in Denver area, along with several others that make us chuckle when we visit.

If you can get one for $20 and have a warm south wall or an L-shaped southern exposure, what's $20? Any more than that isn't worth it for that quality of stock.

davidrt28 - doesn't surprise me that the Niagara Bot Gardens has one - even though they're zone 6 (with winter temps almost as cold as southeast MI), the protected location and lake effect snows make a big difference. I believe there's even a monkey puzzle surviving just up the road in Niagara-on-the-Lake.

Dan - I'm not planning to take a chance on one of the Lowes trees (even for $20) since it's unlikely their trees came from a hardy seed source. Just curious if anyone might know of any trees growing here in the Midwest that derived from a more northern provenance.