What kills bonsai in winter? Some thoughts

[@XaviersBonsaiRetreat]

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

[@GrowingBonsai]

Haha, that would be nice. A fireside chat. It was a little cooler though!

[@bobcatbonsai]

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!

[@GrowingBonsai]

I just wish to remain lazy and not move things around too often!

[@TheBonsaiGarden]

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.

[@GrowingBonsai]

Exactly! Glad to hear this from you!

[@ΒΑΣΙΛΙΚΗΤΖΙΝΙΕΡΗ-η9π]

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 !

[@stuartferris6351]

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

[@GrowingBonsai]

Thank you so much!

[@thenaturecreater8906]

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

[@GrowingBonsai]

sounds too cold for me!

[@thelazybonsai]

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

[@GrowingBonsai]

Well said!

[@FrostBiteBonsai]

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...

[@GrowingBonsai]

I think you should have no trouble if you looked into overwintering a little!

[@guywatson-bognorregisbonsa7370]

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. 😀😀

[@GrowingBonsai]

:) CHange towards warmer or colder is the question then of course!

[@AlexBraunton]

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

[@GrowingBonsai]

I hope so too! Let's see. I think there will be some living left, but I am worried it may have been damaged

[@Darkfire1300]

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!

[@GrowingBonsai]

Curious to hear your thoughts. In a few days a long video on winter protection for bonsai will come out too. Maybe a number of your experiences are covered. But I suppose Idaho is real cold n winter?

[@greenmachinesweden]

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. 🤣😂

[@GrowingBonsai]

:) For all species? I know that many japanese maples are not so hardy

[@greenmachinesweden]

@@GrowingBonsai for all species native to here or classified as hardy to my area. My japanese maples have never experienced colder than -16. And not longer than 6 weeks below -10. So far no problems.

[@thenaturecreater8906]

Så du har de japanske lønnene ute så kaldt i potter uten beskyttelse og det går fint??

[@greenmachinesweden]

@@thenaturecreater8906 they are protected in unheated greenhouse. So no drying winds.

[@akimitussuzukii1834]

@@greenmachinesweden This is really interesting to hear since here in Finland you kind of have to count on that too. However, there are lot of variation between the varieties of japanese maples regarding of cold tolerance. Some japanese maple variants can't handle even -5C and some other can easily survive even from South Finland winters. Like Jelle stated, really depends on the species and even between cultivars within the same species. I have some species and varieties where I don't want to take any risks. For them, I have a small storage room with the small heater that is keeping the temperature just above freezing. although I also have that problem of getting them to wake up too early on spring like Jelle mentioned earlier.

[@koenvanmeerbeeck8724]

another great video Jelle....very clearly explained

[@GrowingBonsai]

Dank je Koen!

[@invinciblecucumber]

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. 😄

[@GrowingBonsai]

Yup, olives deal with low temps. Just the roots freezing solid is not optimal.

[@simontonsornchristiansen1588]

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 🎄🎅🎁🎁

[@GrowingBonsai]

Yes, spring! Would be great to have nice weather again!

[@Darkfire1300]

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!”

[@GrowingBonsai]

I think I would quit bonsai if I were to put so much work in overwintering! But then.. I am in 7A climate zone. Temps pretty much never drop below -20c / -4F where I live

[@Daravenc]

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.

[@GrowingBonsai]

Absolutely. Besides the frost controlling pests, relatively warm coldframes encourage pests!

[@natrjack965]

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

[@GrowingBonsai]

:) Thank you

[@abydosianchulac2]

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.

[@GrowingBonsai]

I would recommend just wait it out. 5c is a little on the warm side, considering it can heat up easaily with warming outside. Maybe keep it protected in a cold shed?

[@abydosianchulac2]

I'd like to keep it in a cold shed, or somehow in a protected exterior space, but I'm afraid I don't have those capabilities where I am now. I live on an urban hill and the only place a tree could be kept outside is in a bit of a wind tunnel between buildings where it's cooled below ambient temperatures. And being in Boston, we could either be in for a milder, snowier winter or one with no snow cover and temperatures regularly around -15 to -20C. I'll try to gauge the situation day by day now (I have a radio thermometer in the crawlspace leaning against the tree), but at this moment I'm less worried about incomplete dormancy than I am sudden killing temperatures from wind chills and the like.

[@GrowingBonsai]

@@abydosianchulac2 sounds like a true bonsai nightmare outside right now! Only Mugo pines like that climate!

[@abydosianchulac2]

As a follow-up, I kept a thermometer with my tree to count the number of cold hours under 5C, and when it has racked up 1000 hours two weeks ago I took it out of storage and brought it into a warm sunny room. A bud started swelling two days ago, so I barerooted it to remove the sphagnum used in the air layering (and also to straighten the many circling roots). And today, all the buds are either swelling or elongating! So challenge 1 completed, now to see if I keep it alive till it can go outside. (And for the record, I only took it out of the attic because it was starting to get warmer up there anyway, and I didn't want it to leaf out without me knowing.)

[@natedykstra1498]

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.

[@GrowingBonsai]

I am looking at the highs

[@Darkfire1300]

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.

[@GrowingBonsai]

I recommend you watching the video lined up for later this week on winter protection :)

[@oachkatzlsmum]

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

[@GrowingBonsai]

Hi Martina, great to hear. A more in-depth one is planned for.. I think Thursday!

[@oachkatzlsmum]

@@GrowingBonsai My experience showed that cold is not the real problem for most of my trees. More important is not to let them dry out. Dry roots as well as too much humidity prohibits their ability to sustain the frost. Keeping the surface of my pots constantly covered with snow, as temperature allows, helps well to come safe through the winter.

[@cor1128]

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

[@GrowingBonsai]

Ha Cor, graag gedaan. Over iets meer dan een week komt er een uitgebreide video online! Dit is een teaser ;)

[@matshagstrom9839]

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

[@GrowingBonsai]

It is a bit tricky. If dormant, light is not really a need. So popping it in a fridge for 2 months might work. Be wary of humidity. Fridges seem to have a low humidity so you need to ensure it is well watered. Is there a local club with people who grow in your climate you could reach out to?

[@TeamFishweights]

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

[@GrowingBonsai]

Win some, loose some!

[@matthewkeogh6439]

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

[@GrowingBonsai]

I can imagine. But then.. Your summers can be brutal!

[@darrinscott3393]

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

[@GrowingBonsai]

If you get temps in the -40 region, I doubt your greenhouse will warm up in the sun very much, but certainly in the shoulderseason I would watch the temps. But.. I am NOT in such a cold climate!

[@Bonsai_jopie]

Bedankt voor de info Jelle👊🏾

[@GrowingBonsai]

Gaarne!

[@ramboke911]

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?

[@GrowingBonsai]

Typically, once they are in, I leave them in untill the world is frost-free and no frost predicted for the 10 day long forecast. I am lazy and do not like to lug things around too much. Especially in the cold, dark winter.

[@phillipwaterman5721]

Bonsai phill very good video thanks jelle keep it up mate

[@GrowingBonsai]

Thanks, will do! So happy you enjoyed this! I recorded a much longer winter video, which should be out before christmas! (in fact, it celebrates my 12 months youtube!)

[@MadeManMafia]

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?

[@GrowingBonsai]

This is a very species-dependent question! I like to have my pots thaw out every 2-3 weeks whenever possible, but I do not typically lug them around. Being frozen so far has not caused me massive problems in itself for most species (mediteranean species excepted) If you have lots of snow and all are burried, people leave them there for months on end.

[@MadeManMafia]

@@GrowingBonsai Nothing more than a dusting of snow so far, and expected to hit -8 celsius later this week. First winter in my new house and the garden is a bit more exposed. Glad to know that being frozen isn't a death sentence for my trees :)

[@GrowingBonsai]

@@MadeManMafia frozen is not really an issue. A more detailed vid coming in a little over a week!

[@MadeManMafia]

@@GrowingBonsai Look forward to it, as with all your vids!

[@kylepurvis6231]

In my experience, native trees that are frozen actually offers some protection to the reefs as there frozen and can’t get any colder! So if temps drop to very cold the root mass stays more stable at freezing. Crazy weather everywhere where so error on the side of caution- place them on the ground take advantage of earth warmth.

[@gayefanner731]

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 🙏✝️ ✌️🇷🇺☮️🇺🇦✌️

[@GrowingBonsai]

Glad you enjoyed it! And welcome back. It feels like have have not seen you here forever!?

[@gayefanner731]

O I do pop in regularly but rarely think of anything to say! ✌️

[@KleinBonsai]

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 😅☔

[@GrowingBonsai]

I can imagine. I supose you use shadecloth in summer?

[@KleinBonsai]

@@GrowingBonsai I have considered it, but at the moment my trees are under other trees. But with the way the seasons are changing I might need it soon. The hail risk is getting higher unfortunately

[@Anarchist007]

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

[@GrowingBonsai]

Hi Anarchist, you think the late season growing was part of the rootwork in early spring? In any case.. It did live and grow in the end! It is now pushing the third time this year!

[@KennetDeBondt]

Hopelijk komt alles goed! Grts Kennet

[@GrowingBonsai]

Optimisme sterft als laatste!

[@BONSAICERIACHANNEL]

Selamat siang hadir paman👍👍🙏

[@GrowingBonsai]

Terima Kashi!

[@dimuthuharshana9602]

❤️❤️

[@GrowingBonsai]

Thank you!

[@TheBhannah]

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

[@GrowingBonsai]

Nah :)

[@BlueJayBonsai]

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

[@GrowingBonsai]

You can never watch old movies again! Unless you the questions, 1 2 and 3.

[@mattbrennan647]

I’ve found that putting rabbits and squirrels on a strict “lead diet” solves the problem. 💀

[@BlueJayBonsai]

@@mattbrennan647 youuuu wascally wabbit!

[@mattbrennan647]

@@BlueJayBonsai shhhhh,, be vewy vewy quiet. It’s wabbit season and I’m a wabbit hunter 😂

[@thelazybonsai]

@@GrowingBonsai Nee!

[@brucedeacon28]

👍👌🙂

[@GrowingBonsai]

👌😘

[@737ngJR]

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

[@GrowingBonsai]

great to hear! Here the same, we had a -20c winter and I did not loose any trees that year. How did you keep them over winter?

[@737ngJR]

@@GrowingBonsai very cheap cold frame. I did cover the small pots with pine bark.

[@akimitussuzukii1834]

@@GrowingBonsai That's great to hear! It sounds so incredible though. Bonsai is typically growing in a pot and rootball is relatively small and containing lots of sensitive fine roots. I guess they will not survive through the -20C if not somehow buried in the ground or covered with the plenty of snow or some other insulator and attached to the ground at same time. Where do you live Jelle? There is a big difference, for how long period of time the plant is exposed to that harsh -20C or even -10C temperatures and also how long is the winter period is as a whole too. People gardening in the central Europe (or even just a south side of the Baltic Sea) don't have to worry that much even if the temperatures are occasionally dropping below freezing or even -5 to -10C, since it is usually lasting just a several days or even just a couple of days. And the growing season is much longer, autumn and early winter much milder and spring is coming much earlier than utmost Northern parts of the Europe. What you think? Pushing the limits and growing zones and trying out risky things is still something worth to try if you can afford it. I have noticed that not only species and cultivar matters but even just a single individuals. Some individuals are just coping and adjusting better than others. Some just have more strength than others. Even within the same cultivar.

[@PoorGuyBonsai]

doom and gloom in Michigan

[@PoorGuyBonsai]

thanks you've been very helpful to me.. I'm going try do the same

[@GrowingBonsai]

Doom and gloom? Too dark and cold, is it?

[@theoschmitt3037]

Da passt total.

[@GrowingBonsai]

hahahaha, ich warte aber bis fruhling bis ich entscheide mein freund!

[@theoschmitt3037]

@@GrowingBonsai ok, nächstes Jahr ist auch wieder Weihnachten. Natürlich hoffe ich, dass keiner deiner Bäume irgendwelchen Schaden nimmt.

[@TycoonMK]

so sad

[@GrowingBonsai]

We will see in springtime! It has taken up some water since and is not soo sad looking anymore

[@andyt3233]

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

[@GrowingBonsai]

Normally I have no issues. In this case, the challenge was because the frost came early (Trees still growing) and I was not home. And it was the first frost, and straight a deep frost.