Overwintering Ideas

[Shaw81]

Im very new to the hobby. Fall and winter are fast approaching its time to start thinking about how Im going to be overwintering my trees this year. Last year I had 4 trees. I mulched in 3 in front of a single pane glass window. I coverd them with a styrofoam box on the extreme cold night. Only 1 made it through winter. Im in USDA zone 6b. This year I have a small juniper in a bonsai pot (the only one to survive last year), a 2.5 ft dawn redwood in a nursery pot, a 18 inch bald cypress in a nursery pot and probably a couple more coming after hitting the clearance sales at the local nurserys. Question is how could I overwinter these tress?

 

[coltranem]

What types of trees did you lose? Do you have a picture of your setup from last year? Is it possible the glass pane made things too warm.

I am in a similar zone to you and the past two winters I have stored all my trees in my bulkhead which stays between 25 F and 35 F most of the winter. This years I am toying with the idea of leaving some conifers outside on the ground in a place out of the wind. We'll see how that goes.

 

[Shaw81]

I lost a Chinese elm and a juniper. The setup was nothing to take photos of. The glass was a basement window that the trees were in front of to keep them from getting to cold on the coldest nights. Was considering building a cold frame of sorts this year but I am concerned with the results I had last year.

 

[leatherback]

How cold does it get where you are?

 

[Cable]

Here's something to consider:

For most trees you're not trying to keep them warm you're trying to keep them cold!

The two biggest dangers in winter (assuming zone is not an issue) is drying out (hastened by wind dessication) and breaking dormancy too soon.

You want to keep trees out of the wind, out of the sun, and once the roots freeze keep them frozen until it is safe to break dormancy.

Here's an article I wrote last year that might help: http://www.clevelandbonsaiclub.org/2018/10/28/best-practices-for-bonsai-winter-care/

 

[Shaw81]

Temperature wise I would say on average low 20s to upper teens. But it can get into the negatives at night on occasion. Cable I did the things you mentioned in your article. I buried the pots in mulch and only covered them when temperatures were expected to get below 15. I dont think covering them in front of the window brought the temps high enough for them to come out of dormancy as it was mostly at night during extreme temps.

 

[Shaw81]

I guess I will do the same thing and pay more attention to soil moisture. It could very well of been a drying out issue.

 

[leatherback]

That should not really be an issue for most hardy species.

Drying out is not soil moisture. It is the soil being frozen and the tree not able to get more water when winds dry out the foliage.

What kills bonsai in Winter? - Growing Bonsai

It is springtime. Slowly the buds of our bonsai start to swell. But some of them don't? Did something kill it over winter? The most common causes of bonsai mortality over winter explained!

www.growingbonsai.net