Spring vs Fall repotting

I am happy this has been settled. Trees that freeze solid die. Just as I posted, perhaps people think their trees are frozen solid not realizing that on the ground the warmth of the earth keep the soil temps above freezing despite the surface of the pot being frozen... Simple aint it ?

ed

You are an idiot
 
This is a slide I lifted from an Arbor-culture class taken this winter: SEE BOTTOM

I have seen fresh root growth in the fall and winter when repotting out of season for what ever reason. I though about fall repots, because i did not want to waist a bunch of root growth every spring.

But there is a good reason not to:




Don't take a chance your trees will make through freezing with fresh cut roots.
 

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At this point i have a lot of trees. I usually move them in and out of the garage during extreme cold snaps. Being tired of this this year I decided to see what would live if left out. I tried this winter to see if a nana juniper and some black pines would live if I left them out during a 13 degree cold snap this winter. They are all dead as a door nail. I don't understand how you guys can leave trees out much colder and they live. I wish my experiment would have gone the other way, but it did not as I'm tired of moving so many trees. FYI I set them on top of a bench with no protection. We also had freezing rain that day.
 
At this point i have a lot of trees. I usually move them in and out of the garage during extreme cold snaps. Being tired of this this year I decided to see what would live if left out. I tried this winter to see if a nana juniper and somlive if I left them out during a 13 degree cold snap this winter. They are all dead as a door nail. I don't understand how you guys can leave trees out much colder and they live. I wish my experiment would have gone the other way, but it did not as I'm tired of moving so many trees. FYI I set them on top of a bench with no protection. We also had freezing rain that day.

Sounds crazy, but I had a conversation with a local meteorologist last year who disclosed that temp estimates and readings are taken a minimum of 4ft above ground. Has something to do with the 'asphalt effect' of temp readings, but the gist of it was if they forecast 38ish it may well freeze at ground level. Not that this is in play at 13, but I found it interesting. Kinda explains why so many products say dont use at or below 40 degrees, the lawyers who wrote the directions built in a safety factor.
 
I am happy this has been settled. Trees that freeze solid die. Just as I posted, perhaps people think their trees are frozen solid not realizing that on the ground the warmth of the earth keep the soil temps above freezing despite the surface of the pot being frozen... Simple aint it ?

ed

The trees I had outside that lived were not on the ground. Last winter and the winter before that (not this year), they were on my bench that is on my deck, away from the house, fully exposed to air, snow, and freezing rain all winter. All 5 trees of different species that were out there froze solid and lived. I still have every one of them outside right now.
 
At this point i have a lot of trees. I usually move them in and out of the garage during extreme cold snaps. Being tired of this this year I decided to see what would live if left out. I tried this winter to see if a nana juniper and some black pines would live if I left them out during a 13 degree cold snap this winter. They are all dead as a door nail. I don't understand how you guys can leave trees out much colder and they live. I wish my experiment would have gone the other way, but it did not as I'm tired of moving so many trees. FYI I set them on top of a bench with no protection. We also had freezing rain that day.

The only trees I leave out on the bench unprotected at temps that low are Rocky Mountain Junipers. All my other trees get placed on the ground when temps are forecast to fall close to 20 F or lower. They all get watered, too, if the soil is on the dry side...dry root balls offer less protection to the roots then moister root balls. I believe BVF left a shimpaku out on his bench this past January when temps fell into the single digits...last word on it was in March and it was doing fine. As others have said, there's a lot more to surviving winter then dealing with the cold. One of the things I feel people often ignore when trying to figure out why a given tree faired poorly over the winter was the overall health of the tree as it entered dormancy. Ryan Neil was the one who told me that when a tree dies over the winter, first look for answers by evaluating the previous growing season for subtle signs of what may have been a developing problem.
 
Personally, I wouldn't dare leave a potted black pine out exposed to temperatures lower than the low 20s, as I've always heard they are quite cold sensitive. I would think a juniper would have a better chance of making it so maybe it already did have problems going into the winter.

As others have noted, there are many factors at play other than the actual low temperature. For instance, how long was the temperature down near 13F? Did it drop quickly into the teens and stay there most of the night, or did the temperature plummet down for only an hour or two? Remember that the air will cool much faster than the soil in the center of the root mass, so if it was 13 only for an hour or two, the bulk of the root mass would have not reached anywhere near that temperature (unless it was windy).
 
My water lines froze this year, that means the ground itself was frozen to a depth of 6 feet or more, at what temp it was frozen at I have no idea. Hopefully trees are all fine, they are starting to poke through the snow now so another 3 weeks or so and I will find out how they fared.
 
At this point i have a lot of trees. I usually move them in and out of the garage during extreme cold snaps. Being tired of this this year I decided to see what would live if left out. I tried this winter to see if a nana juniper and some black pines would live if I left them out during a 13 degree cold snap this winter. They are all dead as a door nail. I don't understand how you guys can leave trees out much colder and they live. I wish my experiment would have gone the other way, but it did not as I'm tired of moving so many trees. FYI I set them on top of a bench with no protection. We also had freezing rain that day.

JKD I had a similar experience 2 falls ago in October. I went to work on a rainy day to a jobsite in northern Ohio 150 miles N. of home. It was in the 70's that morning and we were expecting a cold snap that afternoon with lows in the upper 40's, no problem. I left my plants on my bench and did not get home until 11:30 that evening, the temperature dropped to 18 degrees by 5:00 that evening so my plants had 6 hours before I was able to set them on the ground and put a box over them. I had 3 established pro-nanas and a blue rug juniper, a large collected Florida elm I got the winter before, a brand new Colorado Blue Spruce in a 5 gallon nursery pot I had bought 2 days previous, an established cotoneaster and a big chinese elm that all froze solid. I lost these 8 plants late December - early January. I lost my Tropicals except one that I had just chopped the top off of. I feel that one lived as it did not take up water while it was getting over the chop. My other tropicals wilted and died within days.

After they died I looked at them, the Nanas had the roots seperated as if they had been cut. The new Spruce had the large tap root at the base shredded, it looked like I had taken a knife and shredded the roots. The Elm roots were ripped up and the bottom of the trunk was cracked below the soil, the cotoneaster trunk cracked half up the tree. I also lost two pots and had one develop several cracks.

The rest of my trees survived, they were the ones that were setting in the middle areas of my bench, I feel they were somewhat insulated by the others. I had just worked on my Catlin Elm forest the night before and it was setting on the ground, it had no problems either.

ed
 
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