Winter plans

[Dav4]

It isn't as much about keeping them warm as it is trying to keep them from getting too cold. I think the point of the mulch is to simulate protection / cold buffer for the roots that would normally be provided by the ground.

I know at the nursery where I work we're taking extra precautions this year after noting increased loss the past few years. Most of our shrubs and young trees are wintered in hoop houses, often lying down and covered with a thin foam blanket. This year we're adding hundreds of heaters to the hoop houses to add minimal heat and buffer the extreme cold in an attempt to decrease the loss.

It's as much to keep the root-ball cold/frozen when the temps are abnormally warm in January, February, and March as it is to keep them from getting too cold....

 

[Cable]

That's what I meant by cold buffer. Temperature swings.

 

[cmeg1]

Leaves and straw ain't gonna cut it.

Good point....and straw is a rodent magnet that will get your bonsai girdled at the trunk base!

 

[cmeg1]

I use a well house,

This sounds like some of the best Winter storage for cold climates.I once read in Bonsai Focus? The method of building a shed with dirt floor sunken into the ground and they advocated making the floor mud with a hose and then putting gravel over top for the EXTRA humidity.This keeps bonsai soil moist for really extended times and will not always have to water during dormancy.
When I use a deep cold frame in the shade I do just that.It is great how they stay very cool till all danger of frost passes,so no back and forth stuff in Spring.Someday I will build something big so I do not have to kneel over to get my small trees out of the cold frame...boy they do work though!

 

[Tieball]

I shoveled Michigan sand...beach sand....around boxes during winter. I have winter...I want as much snow as I can get to fall on the trees. I don’t keep trees that won’t survive outside. The boxes and sand keep roots surviving well and no rodent camps. I have extremely cold wind chills also. I deal with the wind by putting up a green mesh fencing. It’s about 48” tall. Does the job perfectly well for the trees needing wind protection. The wind to me is more the winter problem. Once the roots are frozen in an insulated mass that keeps them perfectly fine until spring. If I know there is a potential for a frost, or just very low temperatures, in the spring I mist the trees in the evening cold to put on a good frozen layer...an ice coat. Works well.

 

[Vance Wood]

This sounds like some of the best Winter storage for cold climates.I once read in Bonsai Focus? The method of building a shed with dirt floor sunken into the ground and they advocated making the floor mud with a hose and then putting gravel over top for the EXTRA humidity.This keeps bonsai soil moist for really extended times and will not always have to water during dormancy.
When I use a deep cold frame in the shade I do just that.It is great how they stay very cool till all danger of frost passes,so no back and forth stuff in Spring.Someday I will build something big so I do not have to kneel over to get my small trees out of the cold frame...boy they do work though!

Here is the problem; sometimes a shelter like this can create the very problem you envision. I know of and individual who built a shelter just as described and in the spring found that all of his trees had been devoured at the base. What happened is that the shelter was built and filled before things started to turn cold and the trees, and shelter made a great home for the colony of critters that destroyed his trees. If you read what I said about straw I said not to use it till there has been a heavy frost forcing critters to find their winter homes elsewhere than amongst the shelter of you trees.

 

[Dav4]

Here is the problem; sometimes a shelter like this can create the very problem you envision. I know of and individual who built a shelter just as described and in the spring found that all of his trees had been devoured at the base. What happened is that the shelter was built and filled before things started to turn cold and the trees, and shelter made a great home for the colony of critters that destroyed his trees. If you read what I said about straw I said not to use it till there has been a heavy frost forcing critters to find their winter homes elsewhere than amongst the shelter of you trees.

I once put a fair number of my trees in the basement walk out of a 200 + year old house with a dry laid stone foundation to overwinter.... ONCE! Within 10 days, every maple had been girdled/de-barked completely, as was the base of a grafted JWP- who knew mice would eat pine bark?

 

[Cable]

Ok, most of my trees are put away. I still have three maples which will go into the root cellar but it isn't cold enough for that, yet! Still a little above 40° down there.