how small is it???

that is can be buried in snow cover???

snow cover will probably give you one zone..

and a rose cone also ... until you outgrow it ...

death in winter is RARELY ... temp alone .... which is basically what zone is ... you have to mix in winter winds.. winter drought.. improper planting.... and winter sun ... [and note.. many of those are solved by snow cover] ...

ken

So ok I'm trying to understand your reply. The tree is about 4' tall. But it's by my house and driveway so snow collects there as it falls off the roof and driveway gets shoveled. It will definitely get buried. I'm in zone 5a actually... So you say that snow will give you one zone. That may be the case but I'm still in zone 5a and I still read that these trees don't grow north of where I live. I can look into the rose cone idea but I don't know how big they come. I see your point that the snow can actually be beneficial because it gives the tree water and protects from cold winds. Thanks for your input.