I'd give it a chance. -25 C (= -13F) is just a little outside the range it is rated for. If you had it mulched/ protected, it still might come back from the roots.
I had a redbud tree I thought was dead and intended to pull and then it surprised me and came back from the roots. And I had a little crabapple tree that seemed totally dead, which I did pull and threw on the woodpile. It sat there, roots exposed, no watering, no sun all through the fall and winter and in spring started growing again. I planted it back and it is doing fine!
Trees are tougher than non-woody plants, but still it could surprise you!
What do you have to lose by waiting awhile and see what happens?