Hello,

New to bonsai, I'm preparing my trees for winter in Vancouver BC Canada.
Do you have best practices for Japanese Black Pine & shimpaku Juniper, winter care?
Coldest temperature here approximately 10 degrees below zero Celcius.

That’s no problem to deal with it for either species.

If temps STAY at -10C for days, then you need a cold frame or some protection, particularly if it’s also sunny and windy at the same time: frozen soil means they can’t intake water, while wind and sun are causing transpiration, resulting in dehydration for the trees.
If what you have is “some days with night lows around -10C”, while during the day temps go close (or above) freezing point, those trees are more or less in their natural habitat and there’s nothing to worry about. Just in case try to place them in a spot where they can get light but not too much wind, if you can, but that’s about it...

Thank you Bofhskull.

BofhSkull wrote: That’s no problem to deal with it for either species.

If temps STAY at -10C for days, then you need a cold frame or some protection, particularly if it’s also sunny and windy at the same time: frozen soil means they can’t intake water, while wind and sun are causing transpiration, resulting in dehydration for the trees.
If what you have is “some days with night lows around -10C”, while during the day temps go close (or above) freezing point, those trees are more or less in their natural habitat and there’s nothing to worry about. Just in case try to place them in a spot where they can get light but not too much wind, if you can, but that’s about it...

I'm in Victoria and agree with the above. I keep my trees ON the ground, in sheltered, but exposed to rain and snow location. To keep the pots clean, I place them in shallow cardboard boxes obtained from Costco. I cover more sensitive trees' pots with leaves, or better yet, leave mulch with the layer of 2" to 3" thick.
One caveat: heavy snow may damage some of the branches. To eliminate this possibility, I place some of the trees under the benches. But keep in mind that ALL trees like to be exposed to sunlight in the winter.