What kills bonsai in winter? Some thoughts 

It was like having a fireside chat with Jelle. I loved it and it had some important information to help us all know what we are really achieving and why we may actually be better off leaving the pots where they are. I didnt know the tip about hsoing down the trees for unexpected spring frosts...I need to get someone to stay up late enough to do the hosing :) Thanks Jelle, cheers Xav

Great video Jelle. My local trees in planters get dug in, while my ones in nice pots have a wall of cinder blocks with mulch to bury them. I think like you said it is a dance we have to do for where we live. Thank you for sharing!

Great video Jelle, very knowledgeable. Straight talking and a lot of sense, thanks.

another great video Jelle....very clearly explained

A lot of good information here. Really hoping for my trees to make it through this year. I have far more than I had planned to attempt... It is actually warmer now than it was in November for some reason...

Nice, informative video Jelle. We're fortunate in the UK, especially on the South coast, and I only have to move about 8 trees under cover for the Winter (Ficus, Jade, Zebra tree and the citrus ones). That is at the moment - It may well alter as the climate continues to change. 😀😀

Great to see you again nice sun tan 😎 great video Jelle..

Great video Jelle. 🙏 I will mostly leave my trees in situ on the benches unless we get temperatures colder than -10C consistently, in the UK, which would be quite unusual. The trees have been steadily preparing for the big freeze for the last month or so, shedding leaves and re absorbing chemical compounds, and reducing internal water content, it is more the sudden unexpected temperature drops that catch them unprepared that is a greater danger.

Thanks for sharing your knowledges❤. We have frost in DK for over a week now. My deciduous trees are in the garage but everything else is in the greenhouse. The soils is frost tho, but i dont dare to let them stay in the greenhouse this year. Many of them are “new” so i need to learn and see them the first year at my place. Looking forward to spring already. Merry Christmas everyone 🎄🎅🎁🎁

I have a really long comment about what I have worked out for me in Boise Idaho. so need your permission to add it in. Thanks for the video in any event. It is great!

Great video jelle! I did the same this year i norway. I leave all my hardy trees outside. But the more expensive japanese maple and trident. And some kojo no mai trees. Over winter in the addict of the house. Is freezing coldt there. But they are protect from the cold winds. But the pots are freezt solid now😮 we got 12 to 15 minus now where i live in norway. Very cold for this time of year

That Arakawa is one of my favourite trees. I really hope it pulls through Jelle. The weather at the moment seems to be very unpredictable. In the UK we recently had our coldest day which is a record beaten from 2010. Stay warm mate

Hi Jelle, sorry to hear your trees have suffered a bit. I think you are quite right about winter dormancy, my bonsai teacher has much of the same sentiment and he really knows his stuff. Exposure to frost also for example controls insect populations and diseases. Trees in coldframes and sheds are also often forgotten about and underwatered, out of sight out of mind.

Hi! My problem is that the late years the winter becomes hotter and hotter in my area and my trees wake earlier than usual and I really dont know what what to do to help them.Nice video though !

We sure have different views on how much cold bonsai can handle depending on where we are. In UK they say protect from frost. Where you are people say protect from -10. I just protect them from -20. 🤣😂

I have olive in a pot on my balcony, it survived -7 this winter, grower said it can survive even up to -12... Since we're having almost Mediterranean climate now in Serbia, I'm planning to plant it directly in soil this spring and use it for bonsai cuttings and air layers. 😄

Good stuff... Temperature swings, moisture, humidity, desiccation, freeze, frost, thaw, soil type, all going to be relatively unique to every person... Winter is like watering, we all need the experience

Hi Jelle, at what point do you decide to take them out of the shed again? When the weather forecast is warmer then -5 celcius for a week?

Do this apply to a greenhouse that's not heated with a vent or just a shed I have my Japanese maples in my Greenhouse just wondering cause I live in mn where it get -40 sometimes

When you mention temperature being sustained for a number of days... do you refer to high or low temperatures? In my climate, at least, they're often 20° F different.

Had a similar issue with an acer palmatum I'd air layered and was trying to establish in a large pot so the root mass could support a large cut back in the spring. It was outside chilling in 5 to 15C temperatures to start its dormancy, then we had a week of temperatures suddenly around -5C it sat through while I scrambled for an overwintering spot. The root ball was frozen solid and the leaves still hadn't fully turned yet. It's now in my attic crawlspace around 5C where it'll be for the next few months, hopefully not getting to _warm._ Will see how it survived then; I'm hoping the roots had matured well enough that they were resistant to being frozen so thoroughly.

Really LONG comment: What a great video. Thanks! These are important things to pay attention to. And, this is a prime example that the best answer to a question about bonsai is “it all depends.” I don’t have the same climate factors as do growers in the UK or Denmark or Italy or even across town. Idaho has hardiness zones ranging from 2b to 7a. Boise where I live currently has zones 6b to 7a. But those of us who have been here 30 years plan and plant for zone 5 winters which occur on average every 10 to 15 years. I have multiple microclimates in my yard that would each require very different preparation for winter storage. Temperatures can wildly fluctuate on a weekly basis from 41 to 17 (F) during the day and 33 to 9 (F) at night. I can’t count on forecasts for the Boise airport ¾ mile away because it is at 2800 elevation, and I am down hill more similar to the Boise River also ¾ mile away at 2100 elevation. The temperatures in various parts of my yard have a 7 to 15 (F) degree difference and a difference in how they warm up with sun exposure. Some parts of the yard are subject to the high winds we get with storms, others are more protected by fences, buildings or shrubbery. So after many years of experimentation, I put all the small to medium potted trees (105 of them) in my north facing pool equipment room (on open wire shelves or concrete pads laid over damp sand) after night-time temperatures fall below 32 in my yard for more than 3 days. In the shed, the temperature stays in the 25 to 35 degree range so I can count on 90 days dormancy. If the temps fall below 25, I can turn on a floor heat mat that keeps things above 20 and if the building warms to above 35, I can open the door and run a fan to circulate colder air. I keep tabs on temperatures with 5 different thermometer/hygrometers, that have alarms, in the yard, sheds, under my deck and in the two garages. Since putting this procedure in place, I don’t panic about my maples, semi-hardy or hardy trees on a bitterly cold night or a too warm day. I check on the trees every morning when I go out to turn on the room lights, so I keep close tabs on how everyone is doing and monitor temperature and watering needs. Everything is in a boot tray and the humidity stays high. When watering is necessary, I wait for a day that is more than 40 degrees outside, drag everything out, water if necessary, and then put the jigsaw puzzle back together until the next time, some 4 to 6 weeks later, on average. At repotting time (or early bud break after pruning), I can put the trees back in the shed or in my temporary greenhouse that I put up March 1. The plants can acclimate to the higher light levels, and I can move them out to the lower shelves of the more protected and semi-shaded benches in late April/early May. If frost threatens, I can put blankets over the benches to protect the trees. This has been very successful for me over the past 3 years. So for me, here in the wilds of Boise, Idaho, things seem to be working, keeping in mind that bonsai is always a “work in progress” and “it all depends!”

Jelle, Thank you for another exceptional video. In my area I have the opposite problem and there are no videos addressing that side of the weather spectrum. In San Francisco we get no frost and no snow. Some tree just don't thrive. I seem to loose Japanese white pines after about three years. Hawthorn also seem to like a bit more cold as well. I'm thinking about getting a commercial refrigerator to help a few trees have deeper dormancy. What I am not sure of is if the dormant trees need light or can i leave them in a dark refrigerator for weeks or months at a time. I know losing trees due to a single freeze is more devastating but losing a tree is losing a tree whether it happens over a couple of years or overnight. I suppose I could limit my selection but few of us want to only grow natives or like climate trees exclusively. Any thoughts would be much appreciated by those who have fundamental knowledge of dormancy needs of trees coming from colder regions and especially the potential need for sunlight during dormancy. Mats H

Bonsai phill very good video thanks jelle keep it up mate

Definitiv mein Favorit in Sachen „Wissenswertes zum Thema Bonsai im Winter“ Danke Jelle. Sorry to see your beautiful tree didn’t make it. 😢 Liebe Grüße aus Salzburg 🙋‍♀️ Martina

Jelle weer bedankt voor de info nu weet ik wel zo een beetje wat ik moet doen met mijn bomen .

Bedankt voor de info Jelle👊🏾

That's sad, hope you don't have any more losses! 😔

I forgot to add that the larger bonsai are gathered into the shade behind the huge pine trees with snow heaped on them. Because they don't seem to thaw and refreeze, they survive the winter temperatures just fine.

As an Australian who’s winter is quite warm I’m glad I don’t have this problem

Here in the UK, we've had about a week of freezing weather so far. Every pot is frozen solid and hasn't had a chance to thaw. At what point does a frozen root system kill the tree? How long can the pots remain frozen before damage?

This looks like the 'bad roots fix' from a year ago..! That's sad... really wanted to see this one with leafs..

❤️❤️

Hopelijk komt alles goed! Grts Kennet

I lose more trees in Summer than Winter here in South Africa...Most of the time it happens after a couple of days of rain then I forget to water that one day it was not cloudy and the sun scorched and dried everything out. It sounds silly but it is difficult balancing under-watering during the raining season 😅☔

Selamat siang hadir paman👍👍🙏

👍👌🙂

Put some led’s in your garage to give them some light .

For me, Jelle, your best video. Relaxed, natural, seemed like the real Jelle, keep it up! Good tip that anti frost damage spraying, 4am was when my friend would begin if the temp was right, or wrong! Great to hear you have a wife!! God bless you 🙏✝️ ✌️🇷🇺☮️🇺🇦✌️

I had japanese maples survived 9F (-13C) last winter

Rabbits - it’s always the killer rabbits! 😂🤣🐦💙🐇🐰☠️

doom and gloom in Michigan

Da passt total.

so sad

I bury my pots under the ground then much mulch over it. It works so fucking good I leave the out all year I build a plastic wrap spare box around the plant and put a tight net over it. Try this it works so good I think it’s a great technique