Winter hardiness, zone 5b - 2018-2019 in northern burbs of Chicago

Leo in N E Illinois

The Professor
Messages
11,337
Reaction score
23,254
Location
on the IL-WI border, a mile from ''da Lake''
USDA Zone
5b
I'm in the northern burbs of Chicago, or the southern burbs of Milwaukee. About as many local neighbors work in Wisconsin as work in Illinois. I'm just a few miles south of where the Illinois-Wisconsin border meets Lake Michigan, a little less than 2 miles from the Lake.

This winter 2018-2019 we had serious cold, at least one night reached -23 F which is roughly -31 C, serious cold, but that came with good snow cover. We had a total of 10 or more nights well below zero F, below -18 C. During these episodes, sometimes there was snow cover, sometimes no snow cover. Our last frost is typically sometime around May 15, though sometimes as early as May 1 can be our last frost. Leaves on the landscape trees are just budding out. Forsythia and Redbud are just starting. We average about 100 to 120 growing days between first and last frost. The farm, 9 miles east of South Haven Michigan had nearly identical cold this winter, and about 18 inches, or half a meter more snow than my home in Illinois, but otherwise it was very similar.

So I hate schlepping trees in and out of my preferred winter shelter, and have been experimenting with just leaving trees lay out for the winter. I do take trees off the benches, and set them on the ground. But that is about it. On the ground they do get some thermal buffering from the soil below, and I do group them a bit which gives some wind protection, but largely they all spend the winter pretty exposed. And they do get some sun in winter. I used to think winter sun was the ''boogeyman'', but I have found it is not as big a deal as I thought. I tend to do this only with trees in larger pots, usually gallon larger nursery pots and or Anderson flats. I have found that even ''good'' meaning ''expensive'' bonsai pottery that is advertised as freeze-thaw resistant is often not freeze-thaw resistant. So trees in ''good'' pots get protected in my well house for the winter.

So here are some trees that have done well this winter.

Pinus banksiana - Jack Pines, my 2 in Anderson flats look great, I have a number of seedlings in mesh walled 'Sorce Pots' (@sorce ) and in 4 inch plastic pots. Some of these were left on their benches all winter, the Anderson flats and the majority were set on the ground. All have greened up and new buds are growing this spring. No losses. Jack pines are definitely the most winter hardy pine I know of. 5th year of wintering without protection 100% hardy. In theory hardy through zone 3 - do try them if you are in the northern tier of states. They might not do well in zone 7 or warmer, but in zone 7 you can leave JBP outdoors all winter, so you don't need Jack pine.

Chamaecyparis obtusa - Hinoki - I used to winter these in the well house, thinking Japan is more like St Louis than Chicago. This is the 3rd year I've left Hinoki out on the ground in an Anderson flat, and no problems. I'd say 100% hardy, but do take it off the bench and set it on the ground for winter.

Pinus bungeana - Chinese Lacebark Pines - I have starting 4th year seedlings, some in an Anderson flat and some in individual 4 inch pots. All spent the winter on the ground and no losses, this is 2 winters in a row. First winter after seed sprouted I did move the flats into the well house. I believe this pine will prove winter hardy in containers throughout zone 5. (@Owen Reich )

Celastrus sp. I think C. orbiculatus - Oriental bittersweet - It could be C. scandens, I have not checked. In gallon containers and 4 inch pots, perfectly winter hardy.

Amelanchier x grandiflora - Service berry - have 2 that have never missed a beat, flower buds are just starting to show. This is an underrated member of the apple family, really nice early spring flowers before leaves fully expand. 100% winter hardy.

Tsuga canadensis - I have one in a 5 gallon nursery pot and a batch of 5 seedlings, about 5 years old in an Anderson flat. The Anderson flat stays on its bench, fully exposed all winter, the nursery pot is on the ground - 100% hardy, no sign of any distress.

Acer ginnala - Amur Maple - I have 2, one in a 5 inch pot, one in a 3 gallon pot. Both are more than 5 years old, never wintered anywhere but outside, on the ground. 100% winter hardy.

Malus hybrid - a crab apple, - don't remember which, one of the weeping crap varieties. I bud grafted onto apple understock some years ago when trying to learn grafting. Both pots on the ground, no protection, flower buds are starting to show. 100% hardy.

Pinus ponderosa - Ponderosa pine - I moved these to Michigan because the back yard was getting to shady. Wintered in full sun, just set on the ground. Looking fabulous, healthier than they every looked in my too shady back yard. These really need full sun to stay healthy, sun in winter is no problem.

Picea engelmannii and pungens - Engelmann spruce and Colorado blue spruce - All did well, full sun, just set on the ground. I have a weeping cultivar of engelmann spruce, and one weeper of Colorado blue spruce, also have grafted varieties of blue spruce, all do fine with no protection.

Picea glauca var densata and Picea orientalis and Picea omorika - all do well juet set on the ground and no extra protection.

Wisteria macrostachya - in a 4 inch diameter pot - just set on ground - did fine.

Chionanthus virginicus - American Fringe tree - has done well 2 winters in a row, both specimens are in 5 gallon and 20 gallon pots. - 3 winters and no problems.

Vaccinium corymbosum - blueberries - select cultivars of highbush blueberries - I have explants from tissue culture and various cuttings sizing up to get them big enough that ''the kid'' can see them from the driver seat of the tractor, so he don't mow them over. Will get planted in the field when about 1 gallon size. These all winter in flats, on the ground. No problems at all.

Carpinus caroliniana - Hornbeam - collected one from the farm, does fine in a cut down nursery pot, set on the ground.
Ostrya virginiana - Hop flowered hornbeam - perfectly hardy even in small 3 and 4 inch pots.

Lycium barbarum - goji berry - One gallon container - set on ground - perfectly hardy 2 winters in a row.

Junipers - virginiana, horizontalis - blue rug, shimpaku, itoigawa, & kiushu, - all in various containers, no winter problems at all. The blue rug, J horizontalis got left on top of the bench and had no problems. All perfectly winter hardy.

Metasequoia - Dawn Redwoods - these are outstandingly hardy. I have left them on the ground and on the bench, and all have survived no problems 3 winters. These are much hardier than bald cypress.

Elms - Ulmus pumila - Siberian elm - left outside, no problems, no protection fully exposed. I have not tested Seiju elm yet. It is supposed to be hardy enough.

Parthenocissus quinquefolia - Virginia creeper - this is another amazingly hardy vine, I leave it fully exposed, just set on the ground in winter.

Chaenomeles hybrids -Japanese Flowering quinces - I have the varieties 'Contorted White', 'Iwai Nishiki' and what I believe is 'Minerva' and these get left out all winter. Just set on the ground. they do fine. These are all larger leaf, larger tunks, more robust types. 'Chojubai', 'Kan Toyo' & 'Hime' need protection, these are small leaf types, and seem to be less hardy in a pot. They might be okay in the ground, but in a pot they need protection. So Chaenomeles, are a some can take it, some can not.

**********************************************************************
Failures - or trees I feel I must protect

Ginkgo - for what ever reason, ginkgo are hardy when planted in the ground as landscape trees, but as a tree in a pot I have had no success wintering them on the ground, or on the bench. I bring my ginkgos into the well house. NOT Reliably WINTER HARDY in 5b

Beech - Fagus - I bring these into the well house, have lost all that wintered unprotected. Even though winter hardy in landscape, they seem to be a problem in a pot.

Japanese Black Pine - Pinus thunbergii - in theory they look like they could be hardy in zone 5, in practice they are not. They might survive one or two winters, but usually within 5 years one winter or another will wipe them out. Also, given my micro-climate, JBP do not wake up on time in spring, because I have cool spring weather. They need heat to ''wake up'' - this means they get short changed on length of growing season. This means that many years my JBP can not be treated as 2 flush pines, they barely have time for one flush of growth. JBP are problematic. Especially since my only JBP experience is the cork bark varieties, I don't grow the normal type.

Satsuki azalea - I love them, love the flowers, they are not hardy here. They do well in cold dark storage for the winter, no unusual leaf drop or any reduction in blooming. Well house is mandatory for them. Zone 7, maybe 6b, no need to test them in zone 5.

Taxodium distichum - Bald Cypress - in the landscape these are perfectly hardy, but in pots are marginal. Had them survive some winters, and fail other winters. Have taken to wintering them in the well house. Must be protected in zone 5

Bamboo - Phyllostachys atrovaginata, aureosulcata, Pleioblastus viridistriatus, and Indocalamus latifolius - all 4 species are perfectly hardy when planted in the ground in the landscape - but planted in pots are not quite winter hardy. Must protect bamboo in winter if in pots. Also include Phyllostachys nigra, black bamboo - which is not winter hardy much north of zone 7.

Japanese Maples, - Acer palmatum - need protection. even though hardy in the landscape.

So that is my ''report''
I post this because I hear of many are going through great lengths to protect trees in winter that are species that are more than winter hardy enough. The great thing about leaving them lay out all winter is you never have to do the ''in and out'' dance with them. My back aches at the thought of running around moving trees just before dark to avoid the frost. I refuse to do it. I am just now beginning to empty my well house, most of my local buddies have been doing the dance with their trees for several weeks now.

So get brave, if you have any of the trees on the winter hardy list, don't baby them, just set them on the ground for the winter. It will save your back in the long run.
 

amcoffeegirl

Masterpiece
Messages
2,770
Reaction score
4,794
Location
IOWA
USDA Zone
5b
This is great information.
I am looking to try some outdoor trees again this year. Since I am 5b also I will refer to this list many times this year.
Do you think your crabapple would be as hardy if it wasn’t grafted?
 

Tieball

Masterpiece
Messages
3,099
Reaction score
3,174
Location
Michigan. 6a
USDA Zone
6a
That comment about the Beech - Fagus .....brought to mind the hardiness content I researched a while ago when I learned my zone boundary lines had changed. Several states changed their zone boundaries due to new findings related to the impacts of growing cities, power grids and climate shifts. Impacts like that. Hardiness zones are based on growing in-the-ground with roots in full contact with the earth. That’s why landscape trees survive easier it seems....however, even landscape trees have their temperature limitations. I don’t recall if I read the next comment as part of the article research or elsewhere...the comment was that if something were in a container the advice was to review hardiness as at least full number lower. In other words a 5b would be viewed as if 4b zone for container growing. Wind chill blocking was another subject.
 

Colorado

Masterpiece
Messages
3,106
Reaction score
8,231
Location
Golden, Colorado
USDA Zone
5b
Wow!!! Posts like this bring a tremendous amount of value to this forum. Thank you.

Almost all of my trees - by dumb luck, not by design - are on your “hardy” list. This is very encouraging for me, especially since we very, very rarely get below 0F down on the Front Range. I’ll be doing far less shuffling next year, that’s for sure.

It’s fantastic to have all this information here in one place.
 

VAFisher

Masterpiece
Messages
2,126
Reaction score
8,238
Location
Maidens, VA
USDA Zone
7a
Leo, do you ever experience freezes or hard frosts after your deciduous trees break dormancy? I lost a couple sweetgums in pond baskets last year that way. We had unusually warm weather in Feb which caused everything to start moving and then more cold and freezing in March. I didn't bother to move them in and they croaked. Would you feel the need to protect yours in that situation?
 

sorce

Nonsense Rascal
Messages
32,908
Reaction score
45,579
Location
Berwyn, Il
USDA Zone
6.2
Leo, do you ever experience freezes or hard frosts after your deciduous trees break dormancy? I lost a couple sweetgums in pond baskets last year that way. We had unusually warm weather in Feb which caused everything to start moving and then more cold and freezing in March. I didn't bother to move them in and they croaked. Would you feel the need to protect yours in that situation?

I wrote something recently about lessening confusion and how it relates to early budding.
I believe early budding is caused by human movement and "protection" which leads to the confusion, which is why trees bud early.
In new shade/sun situations, a new place, most severely...the exact places we hide them from the sun....foolishly I believe.

It is backwards of course. We would expect them to wake less. But that isn't how the confusion works. They look for light, know it's there.
For instance.
My trees, are fully aware of the trees in the yard south of them, they will not be confused when the shade covers them all summer. They Myc speak.

However...

If I move them to the side of the house....where light is severely different, they get confused because I moved their "light clock".

Resorce.

Lightclock.

Not Light, and time, as two different things.

But a light clock.

Don't fuck up their lightclock.

Sorce
 

VAFisher

Masterpiece
Messages
2,126
Reaction score
8,238
Location
Maidens, VA
USDA Zone
7a
I wrote something recently about lessening confusion and how it relates to early budding.
I believe early budding is caused by human movement and "protection" which leads to the confusion, which is why trees bud early.
In new shade/sun situations, a new place, most severely...the exact places we hide them from the sun....foolishly I believe.

It is backwards of course. We would expect them to wake less. But that isn't how the confusion works. They look for light, know it's there.
For instance.
My trees, are fully aware of the trees in the yard south of them, they will not be confused when the shade covers them all summer. They Myc speak.

However...

If I move them to the side of the house....where light is severely different, they get confused because I moved their "light clock".

Resorce.

Lightclock.

Not Light, and time, as two different things.

But a light clock.

Don't fuck up their lightclock.

Sorce

Maybe. But I had trees in the landscape wake up early last year too.
 

CasAH

Chumono
Messages
780
Reaction score
1,270
Location
Arlington Heights, IL
USDA Zone
5
This is great information.
I am looking to try some outdoor trees again this year. Since I am 5b also I will refer to this list many times this year.
Do you think your crabapple would be as hardy if it wasn’t grafted?

I have a seed grown crabapple that sat out all Winter with no wind protection, and it did fine.
 

Carol 83

Flower Girl
Messages
11,126
Reaction score
27,129
Location
IL
I have a seed grown crabapple that sat out all Winter with no wind protection, and it did fine.
What size pot? I kept mine in the garage, since they came from Cali, and was unsure how hardy they would be here the first winter.
 

A. Gorilla

Omono
Messages
1,325
Reaction score
2,158
Location
N/E Illinois
USDA Zone
5b
Pinus Nigra
Pyrus-whatever (feral hybridized bradford pears)
European buckthorn
Dogwood (whatever species is rampant in our nook of Illinois)
Euonymous

Add to the list of low maintenance in winter.
 

rockm

Spuds Moyogi
Messages
14,182
Reaction score
22,183
Location
Fairfax Va.
USDA Zone
7
I'm in the northern burbs of Chicago, or the southern burbs of Milwaukee. About as many local neighbors work in Wisconsin as work in Illinois. I'm just a few miles south of where the Illinois-Wisconsin border meets Lake Michigan, a little less than 2 miles from the Lake.

This winter 2018-2019 we had serious cold, at least one night reached -23 F which is roughly -31 C, serious cold, but that came with good snow cover. We had a total of 10 or more nights well below zero F, below -18 C. During these episodes, sometimes there was snow cover, sometimes no snow cover. Our last frost is typically sometime around May 15, though sometimes as early as May 1 can be our last frost. Leaves on the landscape trees are just budding out. Forsythia and Redbud are just starting. We average about 100 to 120 growing days between first and last frost. The farm, 9 miles east of South Haven Michigan had nearly identical cold this winter, and about 18 inches, or half a meter more snow than my home in Illinois, but otherwise it was very similar.

So I hate schlepping trees in and out of my preferred winter shelter, and have been experimenting with just leaving trees lay out for the winter. I do take trees off the benches, and set them on the ground. But that is about it. On the ground they do get some thermal buffering from the soil below, and I do group them a bit which gives some wind protection, but largely they all spend the winter pretty exposed. And they do get some sun in winter. I used to think winter sun was the ''boogeyman'', but I have found it is not as big a deal as I thought. I tend to do this only with trees in larger pots, usually gallon larger nursery pots and or Anderson flats. I have found that even ''good'' meaning ''expensive'' bonsai pottery that is advertised as freeze-thaw resistant is often not freeze-thaw resistant. So trees in ''good'' pots get protected in my well house for the winter.

So here are some trees that have done well this winter.

Pinus banksiana - Jack Pines, my 2 in Anderson flats look great, I have a number of seedlings in mesh walled 'Sorce Pots' (@sorce ) and in 4 inch plastic pots. Some of these were left on their benches all winter, the Anderson flats and the majority were set on the ground. All have greened up and new buds are growing this spring. No losses. Jack pines are definitely the most winter hardy pine I know of. 5th year of wintering without protection 100% hardy. In theory hardy through zone 3 - do try them if you are in the northern tier of states. They might not do well in zone 7 or warmer, but in zone 7 you can leave JBP outdoors all winter, so you don't need Jack pine.

Chamaecyparis obtusa - Hinoki - I used to winter these in the well house, thinking Japan is more like St Louis than Chicago. This is the 3rd year I've left Hinoki out on the ground in an Anderson flat, and no problems. I'd say 100% hardy, but do take it off the bench and set it on the ground for winter.

Pinus bungeana - Chinese Lacebark Pines - I have starting 4th year seedlings, some in an Anderson flat and some in individual 4 inch pots. All spent the winter on the ground and no losses, this is 2 winters in a row. First winter after seed sprouted I did move the flats into the well house. I believe this pine will prove winter hardy in containers throughout zone 5. (@Owen Reich )

Celastrus sp. I think C. orbiculatus - Oriental bittersweet - It could be C. scandens, I have not checked. In gallon containers and 4 inch pots, perfectly winter hardy.

Amelanchier x grandiflora - Service berry - have 2 that have never missed a beat, flower buds are just starting to show. This is an underrated member of the apple family, really nice early spring flowers before leaves fully expand. 100% winter hardy.

Tsuga canadensis - I have one in a 5 gallon nursery pot and a batch of 5 seedlings, about 5 years old in an Anderson flat. The Anderson flat stays on its bench, fully exposed all winter, the nursery pot is on the ground - 100% hardy, no sign of any distress.

Acer ginnala - Amur Maple - I have 2, one in a 5 inch pot, one in a 3 gallon pot. Both are more than 5 years old, never wintered anywhere but outside, on the ground. 100% winter hardy.

Malus hybrid - a crab apple, - don't remember which, one of the weeping crap varieties. I bud grafted onto apple understock some years ago when trying to learn grafting. Both pots on the ground, no protection, flower buds are starting to show. 100% hardy.

Pinus ponderosa - Ponderosa pine - I moved these to Michigan because the back yard was getting to shady. Wintered in full sun, just set on the ground. Looking fabulous, healthier than they every looked in my too shady back yard. These really need full sun to stay healthy, sun in winter is no problem.

Picea engelmannii and pungens - Engelmann spruce and Colorado blue spruce - All did well, full sun, just set on the ground. I have a weeping cultivar of engelmann spruce, and one weeper of Colorado blue spruce, also have grafted varieties of blue spruce, all do fine with no protection.

Picea glauca var densata and Picea orientalis and Picea omorika - all do well juet set on the ground and no extra protection.

Wisteria macrostachya - in a 4 inch diameter pot - just set on ground - did fine.

Chionanthus virginicus - American Fringe tree - has done well 2 winters in a row, both specimens are in 5 gallon and 20 gallon pots. - 3 winters and no problems.

Vaccinium corymbosum - blueberries - select cultivars of highbush blueberries - I have explants from tissue culture and various cuttings sizing up to get them big enough that ''the kid'' can see them from the driver seat of the tractor, so he don't mow them over. Will get planted in the field when about 1 gallon size. These all winter in flats, on the ground. No problems at all.

Carpinus caroliniana - Hornbeam - collected one from the farm, does fine in a cut down nursery pot, set on the ground.
Ostrya virginiana - Hop flowered hornbeam - perfectly hardy even in small 3 and 4 inch pots.

Lycium barbarum - goji berry - One gallon container - set on ground - perfectly hardy 2 winters in a row.

Junipers - virginiana, horizontalis - blue rug, shimpaku, itoigawa, & kiushu, - all in various containers, no winter problems at all. The blue rug, J horizontalis got left on top of the bench and had no problems. All perfectly winter hardy.

Metasequoia - Dawn Redwoods - these are outstandingly hardy. I have left them on the ground and on the bench, and all have survived no problems 3 winters. These are much hardier than bald cypress.

Elms - Ulmus pumila - Siberian elm - left outside, no problems, no protection fully exposed. I have not tested Seiju elm yet. It is supposed to be hardy enough.

Parthenocissus quinquefolia - Virginia creeper - this is another amazingly hardy vine, I leave it fully exposed, just set on the ground in winter.

Chaenomeles hybrids -Japanese Flowering quinces - I have the varieties 'Contorted White', 'Iwai Nishiki' and what I believe is 'Minerva' and these get left out all winter. Just set on the ground. they do fine. These are all larger leaf, larger tunks, more robust types. 'Chojubai', 'Kan Toyo' & 'Hime' need protection, these are small leaf types, and seem to be less hardy in a pot. They might be okay in the ground, but in a pot they need protection. So Chaenomeles, are a some can take it, some can not.

**********************************************************************
Failures - or trees I feel I must protect

Ginkgo - for what ever reason, ginkgo are hardy when planted in the ground as landscape trees, but as a tree in a pot I have had no success wintering them on the ground, or on the bench. I bring my ginkgos into the well house. NOT Reliably WINTER HARDY in 5b

Beech - Fagus - I bring these into the well house, have lost all that wintered unprotected. Even though winter hardy in landscape, they seem to be a problem in a pot.

Japanese Black Pine - Pinus thunbergii - in theory they look like they could be hardy in zone 5, in practice they are not. They might survive one or two winters, but usually within 5 years one winter or another will wipe them out. Also, given my micro-climate, JBP do not wake up on time in spring, because I have cool spring weather. They need heat to ''wake up'' - this means they get short changed on length of growing season. This means that many years my JBP can not be treated as 2 flush pines, they barely have time for one flush of growth. JBP are problematic. Especially since my only JBP experience is the cork bark varieties, I don't grow the normal type.

Satsuki azalea - I love them, love the flowers, they are not hardy here. They do well in cold dark storage for the winter, no unusual leaf drop or any reduction in blooming. Well house is mandatory for them. Zone 7, maybe 6b, no need to test them in zone 5.

Taxodium distichum - Bald Cypress - in the landscape these are perfectly hardy, but in pots are marginal. Had them survive some winters, and fail other winters. Have taken to wintering them in the well house. Must be protected in zone 5

Bamboo - Phyllostachys atrovaginata, aureosulcata, Pleioblastus viridistriatus, and Indocalamus latifolius - all 4 species are perfectly hardy when planted in the ground in the landscape - but planted in pots are not quite winter hardy. Must protect bamboo in winter if in pots. Also include Phyllostachys nigra, black bamboo - which is not winter hardy much north of zone 7.

Japanese Maples, - Acer palmatum - need protection. even though hardy in the landscape.

So that is my ''report''
I post this because I hear of many are going through great lengths to protect trees in winter that are species that are more than winter hardy enough. The great thing about leaving them lay out all winter is you never have to do the ''in and out'' dance with them. My back aches at the thought of running around moving trees just before dark to avoid the frost. I refuse to do it. I am just now beginning to empty my well house, most of my local buddies have been doing the dance with their trees for several weeks now.

So get brave, if you have any of the trees on the winter hardy list, don't baby them, just set them on the ground for the winter. It will save your back in the long run.

Gotta ask how far along in development these are. I understand winter is hardly the "boogeyman" but when you been working a tree for 20 years and you know it's prooooobably capable of surviving a spring cold snap, risking all that work because you "don't feel" like moving inside (where you KNOW it won't be affected) isn't an option--at least for me.

Biggest tree I have weighs 150 lbs or so. I have a number of them that are over 50 lbs. All of them are big bulky dead weight. I don't have help moving anything, so I move everything myself. I learned the hard way last winter that "I don't wanna" can lead to dead trees. Lost an excellent little BC I got from Zach Smith and half of the branching on my 25 year old BC because I got lazy and just "let them be" in a relatively short, not-very-intense week long cold snap in March 2018. Had three 80 degree days at the end of Feb. BC pushed hard, but stopped short of bud burst. Cold, like mid-high 20's--came in for a week or a little more. I left the trees outside under mulch, even though I kept thinking I should prooooobably bring them in. I 've had the same happen with locally collected Carolina hornbeam...Wish I'd listened to that voice inside my head last spring Cost me a lot...Just sayin...
 

Carol 83

Flower Girl
Messages
11,126
Reaction score
27,129
Location
IL
5 gallon nursery pot. Collected and chopped last April.
Mine came in little 2 3/4" pots, so they may have not made it outside I'm afraid.
 

Leo in N E Illinois

The Professor
Messages
11,337
Reaction score
23,254
Location
on the IL-WI border, a mile from ''da Lake''
USDA Zone
5b
Gotta ask how far along in development these are. I understand winter is hardly the "boogeyman" but when you been working a tree for 20 years and you know it's prooooobably capable of surviving a spring cold snap, risking all that work because you "don't feel" like moving inside (where you KNOW it won't be affected) isn't an option--at least for me.

Biggest tree I have weighs 150 lbs or so. I have a number of them that are over 50 lbs. All of them are big bulky dead weight. I don't have help moving anything, so I move everything myself. I learned the hard way last winter that "I don't wanna" can lead to dead trees. Lost an excellent little BC I got from Zach Smith and half of the branching on my 25 year old BC because I got lazy and just "let them be" in a relatively short, not-very-intense week long cold snap in March 2018. Had three 80 degree days at the end of Feb. BC pushed hard, but stopped short of bud burst. Cold, like mid-high 20's--came in for a week or a little more. I left the trees outside under mulch, even though I kept thinking I should prooooobably bring them in. I 've had the same happen with locally collected Carolina hornbeam...Wish I'd listened to that voice inside my head last spring Cost me a lot...Just sayin...

@rockm
Mark
You bring up an excellent point. I did not emphasize it enough. All my drop, plop, leave it where it lays are material that is less than 10 years in my care. Vast majority are in plastic training pot. However, a really nice shohin Hinoki, in a nice pot got forgotten, I didn't remember it until the week we plunged to -23 F, I couldn't find it as it got buried in snow. - 23 F, and it seems no worse for the wear and the pot didn't crack. I would have been heartsick if I had lost it. It was an expensive buy for me, and I had a few years into it. But given its good condition today, I am learning to relax. Seriously, I do understand the point, and you notice I did say this method was a ''no go'' for ginkgo, that is from sad experience. Lost a couple high potential 30 year plus ginkgo trunks not leafing out again on me. I've been raising bonsai in a dilettante way since 1971, and seriously since 2004. I've come to this approach gradually, by testing different trees. I do actually have a few years of experience. I listed specific species, because these are trees I have actually worked with. WIth the species I listed I feel pretty confident that they would do fine, even as fairly old, well developed trees.

I do pay attention to work I have done. IF there was a late summer repot, the tree is marked and goes into protected well house for winter. IF there was heaving pruning and styling over the summer, the trees go into the well house. If something I did leads me to believe roots or branches did not have time to harden off, and prepare for winter, into the well house it goes. New acquisitions always spend first winter in well house, especially if acquired after the summer solstice. I DO LOOK AT THE HEALTH & HISTORY of EACH INDIVIDUAL TREE, before deciding whether to shelter or not. (not shouting, but emphasizing the point each individual tree might need something different)

I really recommend everyone start this with trees that are in earlier phases of training, test it, and see how different species respond. Most of us have mixed collections, but most of us have a couple favorite species, where we have multiples of the same species. Test one or two, until you are confident that it will cope. Then after you both understand your chosen test species response, and the vagaries of your winters, try more.

I have an Itoigawa shimpaku that has spent every winter for the last 18 years outside with no protection. I did not come to claiming they are hardy without experience. It still looks like crap, but that is my lack of artistic skill, not a problem with the tree loosing branches or other health issues.
 

Leo in N E Illinois

The Professor
Messages
11,337
Reaction score
23,254
Location
on the IL-WI border, a mile from ''da Lake''
USDA Zone
5b
Leo, do you ever experience freezes or hard frosts after your deciduous trees break dormancy? I lost a couple sweetgums in pond baskets last year that way. We had unusually warm weather in Feb which caused everything to start moving and then more cold and freezing in March. I didn't bother to move them in and they croaked. Would you feel the need to protect yours in that situation?

I know how to winter trees in zones 5 and 6a, here our winters are ''predictable'', and we are fortunate, the mid winter thaw that we get, normally in late January, or early February is usually short enough that native species don't start growing on me. I did mention I don't use this method for Japanese maples, A. palmatum, and the related japonicum, sieboldianum, and pseudosieboldianum and trident maples. This is because even though they could be hardy, once their chill requirement is met, usually by beginning of January, they will start growing on me at the drop of a hat. 2 warm days and winter hardiness is lost. So these do have to get protection, and fortunately, the below ground well house the frozen soil helps keep the temperatures cold for the short winter warm spells.

I DO NOT KNOW, zone 7 winters. I know you get late frosts many weeks after most plants start to grow. Up here our late frosts are usually within 2 weeks of the time the landscape trees start leafing out. I know in zone 7, you can have trees leaf out by end of February, and still get a frost as late as end of April. Here I would just be forced into moving trees in and out. So your point is well taken, and I am not sure I know the answer.

Note: Japanese maples, because of the island climate, are used to winters that come to an abrupt end. It is to their advantage to grow immediately after the ground warms a little. Japan rarely gets late frosts, and in valleys that face the sea, the ocean heat often protects these areas from frost.

I like using natives, or natives to similar climates, or climates that are colder than mine. The reason, these species won't leaf out too early. Or if they do, they are tolerant of late frosts. My Amur maples are always wintered outside with no protection, they are currently 2 weeks ahead of my landscape Norway maples. THe Amur have leafed out, the Norway maples have not. They are very tolerant of frosts to their foliage after beginning to leaf out. They have gotten frosts, but it does not affect them at all.

THe late frosts are the reason, I suggest using Prunus americanus, the North American native plum, and Prunus armeniaca - the culinary apricot, because they will bloom a little later than Ume, and won't start growing until danger of last frost is past. Both can have frost damage to flowers, but their foliage won't be harmed at all by late frosts, as generally they don't start growing in earnest until well after last frost. For that matter, culinary European plum is also good at not blooming or growing too early.

David Crust, in Minnesota, has been working on a winter storage shed that stays colder, longer. He doesn't have as much time as he needs in spring, and has problems with larches waking up too early, during a thaw, and thus screwing up his timing for repotting and other work. The convention is Larch MUST be repotted before the bud scales of expanding new buds show any green in spring. If you repot later than this point, your success decreases. My experience says his timing is correct. I don't have any larches at this moment, because I did not repot at optimal times. Anyway he is looking in to ways to cool his storage shelter so that it stays below 38 F, or +3 C, during late winter thaws, and into spring, so he has time to bring trees out of storage and repot them.
 

Leo in N E Illinois

The Professor
Messages
11,337
Reaction score
23,254
Location
on the IL-WI border, a mile from ''da Lake''
USDA Zone
5b
@Carol 83
I think your crabs, even as little cutting grown seedlings would be winter hardy in St. Louis area. But pay attention to the shape of any ceramic container, it needs to be shaped so that as the root ball expands when it freezes, it has room to lift up and expand. Pots with angled outward walls are good. Pots with walls that curve inward are likely to break.

David Kreutz keeps his Satsuki in a plastic hoop house with no added heat. He is just ''down the road'' from you. Your crabs should be fine. Satsuki I would recommend some protection, but you don't need a huge amount. Talk with David Kreutz. He could give good local advice.
 

amcoffeegirl

Masterpiece
Messages
2,770
Reaction score
4,794
Location
IOWA
USDA Zone
5b
Fantastic information. Thank you
 

VAFisher

Masterpiece
Messages
2,126
Reaction score
8,238
Location
Maidens, VA
USDA Zone
7a
I know how to winter trees in zones 5 and 6a, here our winters are ''predictable'', and we are fortunate, the mid winter thaw that we get, normally in late January, or early February is usually short enough that native species don't start growing on me. I did mention I don't use this method for Japanese maples, A. palmatum, and the related japonicum, sieboldianum, and pseudosieboldianum and trident maples. This is because even though they could be hardy, once their chill requirement is met, usually by beginning of January, they will start growing on me at the drop of a hat. 2 warm days and winter hardiness is lost. So these do have to get protection, and fortunately, the below ground well house the frozen soil helps keep the temperatures cold for the short winter warm spells.

I DO NOT KNOW, zone 7 winters. I know you get late frosts many weeks after most plants start to grow. Up here our late frosts are usually within 2 weeks of the time the landscape trees start leafing out. I know in zone 7, you can have trees leaf out by end of February, and still get a frost as late as end of April. Here I would just be forced into moving trees in and out. So your point is well taken, and I am not sure I know the answer.

Note: Japanese maples, because of the island climate, are used to winters that come to an abrupt end. It is to their advantage to grow immediately after the ground warms a little. Japan rarely gets late frosts, and in valleys that face the sea, the ocean heat often protects these areas from frost.

I like using natives, or natives to similar climates, or climates that are colder than mine. The reason, these species won't leaf out too early. Or if they do, they are tolerant of late frosts. My Amur maples are always wintered outside with no protection, they are currently 2 weeks ahead of my landscape Norway maples. THe Amur have leafed out, the Norway maples have not. They are very tolerant of frosts to their foliage after beginning to leaf out. They have gotten frosts, but it does not affect them at all.

THe late frosts are the reason, I suggest using Prunus americanus, the North American native plum, and Prunus armeniaca - the culinary apricot, because they will bloom a little later than Ume, and won't start growing until danger of last frost is past. Both can have frost damage to flowers, but their foliage won't be harmed at all by late frosts, as generally they don't start growing in earnest until well after last frost. For that matter, culinary European plum is also good at not blooming or growing too early.

David Crust, in Minnesota, has been working on a winter storage shed that stays colder, longer. He doesn't have as much time as he needs in spring, and has problems with larches waking up too early, during a thaw, and thus screwing up his timing for repotting and other work. The convention is Larch MUST be repotted before the bud scales of expanding new buds show any green in spring. If you repot later than this point, your success decreases. My experience says his timing is correct. I don't have any larches at this moment, because I did not repot at optimal times. Anyway he is looking in to ways to cool his storage shelter so that it stays below 38 F, or +3 C, during late winter thaws, and into spring, so he has time to bring trees out of storage and repot them.
Thanks Leo. Great info. I know I'm being over protective but at least for now I don't mind the extra spring work that comes along with that. Someday that'll probably change
 

Leo in N E Illinois

The Professor
Messages
11,337
Reaction score
23,254
Location
on the IL-WI border, a mile from ''da Lake''
USDA Zone
5b
Pinus Nigra
Pyrus-whatever (feral hybridized bradford pears)
European buckthorn
Dogwood (whatever species is rampant in our nook of Illinois)
Euonymous

Add to the list of low maintenance in winter.


I agree, I personally have not tried European culinary pear, or seedlings from them. Nor have I tried Callery pear (Bradford pear & related cultivars) Pyrus calleryana. I'm certain they are more than hardy enough. Both are almost considered invasive species around here. European culinary pear, has the issue of being a bug and disease magnate. the one we have on the farm is rotting apart, fire blight, and at night when you kick over rotten pieces on the ground, foxfire. But there is no doubt that they are hardy in zone 5, likely throughout zone 4.

Pinus nigra - I forgot to mention I have a few seedlings, never once brought them inside. They are approaching 7 years old each. Originally bought to be grafting understock, never got a graft to take.

Japanese white pine, Pinus parviflora, - I have 2 seedling that are starting their 3rd growing seasons. Both winters were outdoors. I have 3 grafted JWP, these are starting 4th growing season post grafting. THese have been fully hardy the last 2 winters. JWP on its own roots is zone 4 hardy according to the books. Grafted JWP are only as hardy as their understock otherwise. I was told my grafted JWP were on Scot's Pine. So far so good.

EWP - Pinus strobus - Eastern white pine - I always leave these out. They are not a good species for bonsai, but I keep a few around none the less. Originally intended to use them as grafting understock for JWP, to get better winter hardiness out of a grafted tree. Never got a graft to take. I will try again at some point.

Black Willow - Salix nigra - I have left a few out all winter. No issues.

I have not tried Euonymus nor Buckthorn (Rhamus) but I trust you are correct. I've seen Sorce's in his backyard. With dogwoods, Cornus, I think results will vary depending on whether you take a local from the landscape or a select nursery cultivar. The gray and red twig dogwoods are incredibly hardy. If your Cornus florida is sourced from southern stock it may have winter issues. I lost a Cornus kousa over one winter, I do not know if winter was the cause or something else I did. In theory Cornus kousa should be more hardy than Cornus florida, and more disease resistant. I just don't know.
 

Carol 83

Flower Girl
Messages
11,126
Reaction score
27,129
Location
IL
@Carol 83
I think your crabs, even as little cutting grown seedlings would be winter hardy in St. Louis area. But pay attention to the shape of any ceramic container, it needs to be shaped so that as the root ball expands when it freezes, it has room to lift up and expand. Pots with angled outward walls are good. Pots with walls that curve inward are likely to break.

David Kreutz keeps his Satsuki in a plastic hoop house with no added heat. He is just ''down the road'' from you. Your crabs should be fine. Satsuki I would recommend some protection, but you don't need a huge amount. Talk with David Kreutz. He could give good local advice.
Thanks Leo, guessing he's in St. Louis. I'll see what Google finds. Great and helpful advice, as usual.
 
Top Bottom