Juniper - overwintering

[Krone]

Hey.

It's the first year that i have a juniper (Juniperus chinensis). I have my trees on a terrace (i leave in an apartment) and in the previous year, during the winter, i have put them on my balcony with a roof (no direct sunlight) to protect them from frost. I even put the smaller ones in the styrofoam.

That being said, what should i do with the juniper? Does it need the light considering the fact that it (obviously) doesn't drop the foliage?

 

[Mayank]

It needs to be outside for sure. It doesn't need a lot of light, just ambient should be OK. I used to think that neither evergreen nor deciduous need any light over winter but I was told that the evergreens do need some light, just not a lot. That being said, all of ours were in the garage last winter (do not recommend for evergreens) and pulled through (except for one small JBP).

 

[Wires_Guy_wires]

Junipers, spruce and pines are the only trees I haven't protected over the course of three winters. Some have been on the bench the entire winter, others on the ground.
They all came out unharmed.

 

[Leo in N E Illinois]

@Krone
You are in zone 7b. I would think your Juniper chinensis would need zero protection for the winter. I am in zone 5b and I leave my Juniper chinensis exposed, with the pots simply set on the ground for the winter. I would think you could either just set yours on the ground, or you probably could just leave them on the bench for the winter. I leave mine exposed. They are very hardy.

 

[sorce]

"ice forms on bridges first"

Best to put insulation underneath, where the roots are, rather than overhead.

Protecting the top confuses them.

Protecting the roots is necessary.

Sorce

 

[PABonsai]

"ice forms on bridges first"

Best to put insulation underneath, where the roots are, rather than overhead.

Protecting the top confuses them.

Protecting the roots is necessary.

Sorce

Are you suggesting putting insulation under pots? If not please clarify.

Putting insulation underneath a pot would work to keep the pot at air temperature rather than ground temp. That's not a good idea.

 

[sorce]

Are you suggesting putting insulation under pots?

Since he's on a balcony, butting the insulation, I envision foam board, against the warm building, black rubber mulch over the pots would be best, care taken to not have it become too hot in spring.
Removing the mulch when sub freezing temps are thru perhaps.

Sorce

 

[WNC Bonsai]

I would take an old styrafoam cooler big enough for the pot, chop down the sides so it is just deep enough to hold the pot, and fill it with pine or oak bark chips or any other mulch deep enough to cover the soil. This will help protect the roots and help hold moisture. Poke a chopstick in the soil so you can periodically check the soil moisture in case it does need occasional water. I am in zone 7a and I gather my trees together in a shaded area and cover them up to the lower branches with leaves.

 

[PABonsai]

We would need to know balvony construction first. Is it a wood balcony or is he in a tower where it's likely concrete? If it is a new building it might even have thermal breaks in the slabs. All very important.

 

[sorce]

We would need to know balvony construction first. Is it a wood balcony or is he in a tower where it's likely concrete? If it is a new building it might even have thermal breaks in the slabs. All very important.

Amen!

Sorce

 

[Cable]

I used to think that neither evergreen nor deciduous need any light over winter but I was told that the evergreens do need some light, just not a lot.

That's what I had thought, too, but I posted about it last year and several people told me the amount of photsynthesis that takes place in the winter isn't enough to make much of a difference.

 

[sorce]

The truth still remains, no one shades natures trees, and nature does this better than humans.

Sorce

 

[brentwood]

We are 6a around here, did mulch around the pots, learned later that wind breaks are recommended. I bought burlap and posts, plan on putting a cloth fence around the pots this year to help with them drying out in our windy Winters.
Brent

 

[Mayank]

We are 6a around here, did mulch around the pots, learned later that wind breaks are recommended. I bought burlap and posts, plan on putting a cloth fence around the pots this year to help with them drying out in our windy Winters.
Brent

That's what I've done in the past. Drove in wood stakes and used two dates of burlap for wind break. And when it snows as long as it's soft and fluffy I shovel a bunch on the trees to cover them.

 

[canoeguide]

I would take an old styrafoam cooler big enough for the pot, chop down the sides so it is just deep enough to hold the pot, and fill it with pine or oak bark chips or any other mulch deep enough to cover the soil. This will help protect the roots and help hold moisture. Poke a chopstick in the soil so you can periodically check the soil moisture in case it does need occasional water. I am in zone 7a and I gather my trees together in a shaded area and cover them up to the lower branches with leaves.

I've seen coolers mentioned in several places, but I'm missing what value they might provide. Does the styrofoam cooler do anything in this scenario other than serving as a container? I ask because they can be insulative (obviously) but if they are not sealed shut, and the contents are at air temp (which they will be after a day), then I'm not sure what the significance of the cooler actually is. This would be like putting a 6-pack of beer cans in a cooler with no lid for a month and expecting it to stay cold: that beer is going to be air temperature or very near it, right? Thermal mass might play some role in smoothing out the highs and the lows (which is part of what we want for bonsai) but does the cooler play a role in that? Hmm.

 

[WNC Bonsai]

I've seen coolers mentioned in several places, but I'm missing what value they might provide. Does the styrofoam cooler do anything in this scenario other than serving as a container? I ask because they can be insulative (obviously) but if they are not sealed shut, and the contents are at air temp (which they will be after a day), then I'm not sure what the significance of the cooler actually is. This would be like putting a 6-pack of beer cans in a cooler with no lid for a month and expecting it to stay cold: that beer is going to be air temperature or very near it, right? Thermal mass might play some role in smoothing out the highs and the lows (which is part of what we want for bonsai) but does the cooler play a role in that? Hmm.

The bottom of the cooler would serve to insulate the plant roots from the cold terrace floor which I assume is concrete. The sides and mulch would also help prevent rapid temperature changes and may help prevent the roots warming up a lot on warm days in winter and breaking dormancy early.

 

[Krone]

We would need to know balvony construction first. Is it a wood balcony or is he in a tower where it's likely concrete? If it is a new building it might even have thermal breaks in the slabs. All very important.

9th floor, concrete construction, protected from wind, left and right side of the balcony are concrete walls, the fence of the balcony is made from copper sheets so the fence so the wind can not blow through. Roof also concrete and floors of my balcony are basically roof to the balcony bellow me. I hope i have explained this good enough. The building is older but there is an air bridge in the floors.

 

[Captain.Bonsai]

I’d also like to learn more about photosynthesis activity levels in winter vs summer and deciduous vs evergreen. Everything I’ve read has been quite vague. I haven’t seen a reference to specific academic studies.

I’ve also read vague statements about green bark deciduous trees performing photosynthesis without leaves but haven’t seen qualifying or quantifying literature.

 

[sorce]

I’d also like to learn more about photosynthesis activity levels in winter vs summer and deciduous vs evergreen. Everything I’ve read has been quite vague. I haven’t seen a reference to specific academic studies.

I’ve also read vague statements about green bark deciduous trees performing photosynthesis without leaves but haven’t seen qualifying or quantifying literature.

Ryan Neil has a good thing about it.
Doesn't get any better than having a tree degree specifically obtained to be better at bonsai.

Sorce

 

[Bonsai Forest]

Junipers, spruce and pines are the only trees I haven't protected over the course of three winters. Some have been on the bench the entire winter, others on the ground.
They all came out unharmed.

How about if a juniper Procumbens recently had a few branches removed and some wiring applied. Thus far I have my junipers and spruces and crypto BD grouped together on the ground, using pine bark straw to protect containers, and covered with light tarp at night (Charlottesville, VA - zone 7b)