Winter in zone 5

I am wondering what to do with my potted browns yew, icee blue juniper (juniperus horizontalis 'monber'), and baby blue sawara cypress (chamaecyparis pisifera 'baby blue') this winter? Do they need to be in the ground or will they be ok in pots? They are young yet as am I to bonsai.
Thanks in advance

Hi,

First thing, you should mention your location in your profile: people from the same region might give you sound advice based on their own experience.

As far as I know, USDA zone 5 means that temperatures can go down to minus 29° Celsius (I prefer to use this standard unit for many reasons, the first one being that most of the world uses the decimal system: 0° Celsius, ice forms, 100° Celsius, water boils, easy peasy )

I don't know about the others, but the yew should be OK, although we don't know how long these very low temperatures can last. If you can bury your pots up to the first branch against a wall of your house, that would be a means to get them through the winter. Adding dead leaves on the ground to insulate the root ball would help too. Make sure that the soil underneath ios well draining to prevent root rot and it should be fine.

Where I live in zone 8 (central France), I've dug a 25 cm deep patch against the limit of my garden (ten inches). I put a layer of zelkova leaves at the bottom (I have three 10 metres high zelkovas in my garden, they don't carry any diseases or fungus), I put my pots there and add more dead leaves on them. If you have pine needles at hand, that's excellent too.

Hi J,

I'm not sure if you are asking to take young plants out of bonsai pots/ nursery pots for winter in the ground or whether to leave them in pots ?

I live in zone 4 and would recommend leaving the trees in their pots IF the pots can be frozen. Most of my pots are made by Minnesotan Sara Rayner who has designed her pots to withstand freezing whereas many cheaper ceramic pots would break.

What you need to know is that your indigenous trees need protection not from freezing but from wind,small animals and sun which will thaw the roots . This thawing will happen several times and possibly kill the tree. Our bonsai club suggests situating the trees somewhere sheltered from wind and sun. Cover the trees with oak leaves or a tree leaf that will not break down such as red maple. As soon as it snows shovel it onto your trees and keep them covered until they can be returned safely to the benches in the spring. I would also encourage the use of chicken wire fencing but if the snow is deep may not stop a hungry bunny. Some people sprinkle moth balls around the pots to discourage mice and voles.

Good luck!
Norma

I live in Zone 5.

Last year was the first year I used a cold frame with a heat source that turned on if the temps in the cold frame got to 35*F and shut off at 45*F. I placed the heat source low and the temperature control high. The trees were all placed on boards approximately 6 inces off the foam insulation I used on the concrete pad.

Prior to that, I made an annual "U" shaped confinement shelter out of bales of straw against the South wall of my basement (surrounding a basement window for a little heat transfer). I would break out an extra bale of straw to make an insulated bed for the trees to sit on. Then I placed boards across the bales and spread flakes of straw on the boards. Lastly, I threw a tarp over the whole structure to keep the wind and rain from deteriorating. The trees went into the cold storage before the temperatures dipped below freezing, but not much before then. When we would get a warm spell I would uncover the trees and water them.

Either way, I don't take the trees out until average nightly temperatures are at or above freezing.

Tropicals go to the office or to the basement.

This year will be challenging since my collection of 4 temperate trees has grown to 40+ in bonsai & potensai.

forbey

Hi forbey,
Just so we understand ... what you are describing is a cold frame so trees do not freeze .. correct?

I have a cold room in my basement dedicated to trees that need dormancy but I also leave trees [indigenous] that can tolerate freezing of the roots outside in the winter. Trees like larch, nursery trees, pines ,spruce , honeysuckle , siberian elm ... This is the set up I was explaining to J .

By the way... I love the bagpipes too !! Genetic memory??

Norma

Most of my temperate trees could freeze, the pots, maybe not. I believe that freezing is not required for temperate trees to go dormant. So I put all the temperate trees in the cold frame to be on the safe side. Some of the hardier species are stored further away from the heat source, but the cold frame allows the trees to go dormant and at the same time keeps them out of the wind.

As I get more comfortable with the tolerances of my trees I hope to allow some to stay out year round.

I look at photo blogs of experienced bonsai enthusiasts (and masters) (Wolfgang Putz is one) I am envious of the snow covered trees in their back yards.

So far, the paranoia is more about root balls freezing and pots breaking but I am willing to repent!

forbey