That’s pretty awesome. Fingers crossed!
Vaughn’s prices seem very low, as well, and no minimum order.
Based on that review, would love to go Guardian, but I don’t think I can get one this year, unless a local nursery happens to know what they have. Now I have to decide… wait until next year or go with an unknown (or other) root stock.
Where you located in IA?
Oh the -30F was the previous winter (2018-2019). Not the last (2019-2020). The lowest we had this last winter was about -13F.
Even so, we had little to no dieback in 2019 from the -30F.
The peach varieties we have are mostly the NCSU releases. Challenger, Intrepid, Contender, and Carolina Gold. And my dad also has a Veteran peach. I had a Redhaven that survived near -25F too at my old house.
@rossn - I’m in East Central Iowa - Cedar Rapids. Zone 5a, but my dad is more firmly in Zone 5b and is almost always about 5 degrees warmer.
Levers - Having been there a bit previously, I figured you would give me a quadrant, but ‘East Central’ is close enough 
Here is an interesting, recent and relevant study by Colorado State on Peach (and Apple and Cherry) root stocks - hardiness, tree size. They also used DTA. One interesting comment they had was that “Excessive growth might interfere with fruit quality”. Maybe that is widely known in the fruit community, and I’m not quite sure if they mean before the tree is mature, or in any given year. Going along with that, is the interesting fact that Guardian produces a peach tree a fair bit larger than Lovell… curious if anyone on Guardian noted lesser fruit quality.
Just to tag onto an old thread. I have peach and nectarine on Nemagard in there 5th leaf no issues. Also have apricot on Lovell no issues. We had -17 last winter and some extremely quick large fall temperature swings. Mike.