Dangers of zone pushing

I am in zone 5b. I see many many peaches, pluots etc. that are rated at minimum zone 6.

I was wondering about the downside of growing a z6 in Z5b. Is it that some years I will lose the fruit or is it that the whole tree will be killed?


The danger is losing the tree, not just some fruit. Zones are averages, not absolutes, so it’s not like every winter would kill a particular tree dead, but the average one would. But if you really want something, you could find a spot on the south side of your house (usually a warmer microclimate) or grow in containers you can bring inside.

The year your on vacation a thousand miles away and the unexpected storm comes up is usually the end of the tree.

Trees will be killed at a certain temperature. If its going to get to that temperature, you will have to protect the tree. Where there’s a will, there’s a way.

On the other hand, apricots are just fine in my area, but the temperature cycles mean it will blossom during freeze times

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A fruit that ripen in July in California ripens in September here.

Half of your garage can be consumed by containerized trees for 4+ months.

Yields are probably lower.

Outside trees can be vaporized if record cold threatens during winter.

Mike how cold does it get there? I’m in 5b and I have peaches and pluots. My pluots lost some buds this year, but probably 100 left. My peaches will have to be thinned heavily. All depends on your low. Are you above -20F as the coldest? That is the temp peach trees die. Fruit buds at about -13. Now I have the Great Lakes to help me along, so one zone 5 is not like another.


This year the coldest got down to -8 to -10.

Talking about stone fruit…
Two winters ago, the first time I heard of “polar vortex” which was colder for longer there was no fruit but the trees were fine. Also the trees were younger only 2 years in the ground do that might have been one reason for no or low fruit.


I also spray them with Wilt Stop. I had fruit 2 winters ago with the low at -16F. I used Wilt Stop, seemed to work. Worth trying. Spray twice if possible. Good for about 90 days, but if you can get a 2nd coat on 30-90 days do so. it must be above freezing and sunny. So some years your may not get fruit, but your trees should be fine. Worth trying IMHO.
I’m getting fruit on every tree this year. The late freezes got my pluots a little. But the peaches look untouched. Tonight should be the last night below freezing here, but just barely. I’m leaving figs out Friday. Yes you can even grow figs, if you have an attached garage or willing to bury them.

I’ve been searching through the forums for pluot hardiness and keep seeing mentions about peach trees not working well in zone 4 or colder than -20 F…

I’m in Utah in zone 5b/6a at 4500 ft and in the last 12 years we hit -25 F for three consecutive days in 2017 and -22 F for five consecutive days in 2011 and all three of my peach trees did fine. All of my trees did fine - nectarines, peaches, plums, sweet cherries, apples, pears…No die-back at all with no fruit loss the following year. The trees aren’t in any particular micro-climate within the yard or neighborhood.

I wonder if our dry climate or dry snow has anything to do with how impactful a cold temperature is?

Maybe? Very strange, the trees should have died. Mine have hit -12 here, and all the fruit buds were dead. the trees were fine. Bush fruit did fine, especially currants.
Well your story reminds me, one really needs to find out themselves. I have mostly Zaiger bred trees, what I bought. I was told it was a rookie mistake. Well I still have all the trees 8 years later. I love them!
I’m very happy with my selection of fruit. I have grafted others unto the trees and it makes for some interesting photos of trees in flower.


@drew51 I looked into this a little more. The airport is the main weather station when you search our town and it was -25 F on those days. It’s about 6 miles away. I found a more local station on my side of town, more densely populated and perhaps influenced by the mountains and slight elevation changes - it was -17 F. So that helps explain it perhaps.

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At the -20F range it’s very important what the prior weather has been like and the stage of dormancy of the tree. The best prior weather is many consecutive days below freezing. When it stays below freezing all day long the tree in mid winter gets hardier every day until it reaches the maximum hardiness possible. In fall or after the tree starts to come out of dormancy it isn’t nearly as hardy.

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Coldest temp for me last winter was -16F and had less then 10 days below 0F. I had bud damage especially on Raspberry Red Nectarine and Trilite peach plum (that had exactly 1 flower open). RR i think had a couple blooms open. One other peach right next to these (forget the variety) had zero. Maybe these varieties just can’t handle even that cold of temp or maybe its just local conditions are garbage for these trees (they are south facing trees…winter sun is no friend to zone stretching). I’m giving them this spring and if nothing i’ll remove them.

A saturn peach had a full bloom but that is in a different area of the yard and that variety is very hardy (although i’m kind of done with white fleshed peaches//not a fan).