I’m who you need to talk to. Dm me if you want my cell # so we can comminuted more easily.
I live in SC zone 8 and our average low is around 16 here in town. I started my in ground “experiments” for the same reason as you…too big to move in and out and running out of groom space.
I have had a lot of success and learned a lot along the way.
Important things to consider:
-Variety and it’s particular cold hardiness
-Site Selection
-Irrigation/Fert
The site selection part is very important to me as I’ve found that if you can get large rolls of heavy duty frost blanket you can plant trees in a row which makes it MUCH more feasible to protect them on shorter notice(important)
-I used plastic on top of my 6oz frost blanket in Dec 2022 and that was overkill. With the frost blanket/4strands T9 lights/plastic It was a solid 40degrees in there at the morning of 16degrees outside..I measured
The low of 2023 was around 18 and all I did was the frost blanket and lights strands again without plastic. The temp inside dropped to 28 briefly but never below that. The thermometer was low on the trees too..not near lights.
Results have been very fun and encouraging so far…although I am not remiss to the fact that this could all end tragically but hey you only live once right. Why not.