Frozen rootstocks

I’m hoping someone can shed some light on the subject of apple tree rootstocks (M111) viability after being frozen solid for a few days. I had the rootstocks tucked away in my neighbors walk-in cooler with the temperature set at around 45F….well here in NH the temperature dropped to about 15F for a couple nights and highs in the 20’s, and the cooler temperature did the same.

I’m just wondering if the rootstocks are still any good? I brought them into my basement yesterday which is hovering around 50F. Crossing my fingers, as I have a few hundred dollars invested in these fellas.

If they are truly still dormant, probably OK.

If they had fresh roots and budding out, probably bad deal.

1 Like

I would be willing to bet you will be just fine. The way I think about it - anything hardy to the temperature you’re worried about should be able to survive it, even if it started to wake up. It sounds like they were still dormant waiting to be grafted.

Bonus - if you have any extra big roots, use em! Milking Rootstock (micro-grafting)


Well what are you going to do, toss them?

I have read exposed roots are 2 zones more sensitive than roots in ground.

I see 2 options. Bench graft and plant and see what happens or if you do not want to risk wasting time grafting, just plant the root-stock and if they grow bud graft in the summer or just wait and graft next year. Honestly, you do not loose much time bench grafting year zero vs grafting onto established roots in year 1. At year 2 they are nearly the same size, just might have a few more laterals on the bench grafted version BUT those laterals are generally too low anyways so you usually prune those off.


Well, if that’s the case, 15 degrees F would be zone 8 so the roots should be fine… I’m sure M111 is hardy to at least z5 right?

Not if the M111 root has put out leaves and roots…it’s maybe zone 9 hardy!

Fully dormant M111 with good snow cover is hardy to at least -38


I kept my first grafted quince in a dorm fridge, maybe a couple of weeks, it was frozen when I took it out. No issues.

1 Like

I’ve lost too many M111 over past 8 or so years at around 15-19 degrees after small leaves came on them. (these in containers). Only root I’ve had the issue on.

1 Like

It sounds to me like these are fully dormant in storage though… Is that the case @royce?

On what do you base this extra-vulnerability of roots that have begun growing roots? It is logical but it is also logical that hair roots killed will not kill the main roots that generate them which occasionally is the case with nursery trees I have where they are healed in until June and transplanted then, killing the first flush of new root. If the first burst of roots dry up it will reduce first year vigor but I wouldn’t assume death was inevitable or even likely- unless I had experience or research that convinced me otherwise. Tree roots never go entirely dormant and generate new roots even during winter.

I share my experience and evidence on many a topic that you’ve flagged and had removed. I am tired enough of it that I’m saying nothing more. My anectdotal statement is just that, and given to be hopefully helpful to someone.

1 Like

I have never flagged any or your comments (staff doesn’t do that) and I don’t usually remove them unless I’m sure the rest of staff would agree (I make sure they know so if they don’t we would put the comment back up- but with you, that hasn’t happened). All I was doing was asking what your conclusion was based on- if it is anecdotal, why not share the specific anecdote?

People often get offended when I question their conclusions (I rarely get a like for doing so) but if I’m unaware of the science, I am curious what such claims are specifically based on. Some people, instead of getting offended, provide me with a link to research that indicates the validity of their claim or the background of their anecdotal observation, which gives their comment substance and I believe makes it more useful to everyone.

Yes, they are. I called Fedco today and they reassured me that they would be fine. I’m totally new at this, so I reached out here before asking the supplier.


There is no such thing as a stupid question! Keep asking questions when you have them, there’s almost always someone here who is happy to help.

1 Like