Warmer Climates: People's solutions for controlling nature/mimicking winter (or how to induce overwintering in trees when no seasons to speak of)

[Emanon]

I have seen numerous threads on this forum that deal with how to handle trees in the winter, in colder zones -- i.e. threads on how to prevent roots from freezing. This includes the creation of special rooms or growhouses, and/or complete overhauls of existing rooms such as garages. In some of these threads I've seen members of this forum get very creative with their intricate modifications (heat mats, instead of carpet, that are on timers, etc.). But, as far as I can tell, these types of threads -- where people get very creative in "controlling" nature -- deal with making extreme cold climates tolerable for trees that aren't used to such coldness. And when people do discuss warmer modifications for extreme heat, the solution is always the introduction of increasing levels of shade cloth and misting. (I was out watering my "full sun" junipers today and noticed that it was so hot, transpiration was hardly taking place, and, when shaded, the high heat remained and the non-evaporating water was probably just stimulating the growth of dangerous mold.)

Anyway, my main concern here is the complete non-existence of winter where I live (Southern California). And I know people on here can come up with some pretty crazy, probably excessive, far out there designs for rooms built to control or reconfigure nature. If people can grow Southern California-native junipers in Minnesota, or the Mid-West, or anywhere where it snows in the winter...we here in Southern California should be able to grow trees that need a freezing cold winter. Or, at least, the creation of a colder winter should allow us here to grow healthier Japanese maples (or other PNW climate-adapted trees). Has anyone (engineers by profession maybe?) built a "cold room" for trees? Has anyone modified air conditioning units, for example, to create something like a cold mat? Blocks of ice are impractical (they would melt)...I was thinking creative uses of refrigerants (Freon, etc.)... I'm just curious what people have come up with...

 

[Bonsai Nut]

Overwinter them in Big Bear

I'm not kidding, I had heard that there was a nursery with a greenhouse up there that offered tree wintering services. Whether it is just a rumor or not, I was never able to determine.

 

[Emanon]

Overwinter them in Big Bear

I'm not kidding, I had heard that there was a nursery with a greenhouse up there that offered tree wintering services. Whether it is just a rumor or not, I was never able to determine.

You know what?! I had similar idea last time I was up in Julian/Mt. Laguna (which is like 45 minutes from where I am on the coast here)! But my thinking was limited to: "Oh, I wish I could just leave a pot some where out here in the woods and still have it get enough water. I'd have no problem coming up every time it snows to take it indoors. (We go up pretty much every time it snows there anyway.)" lol I'll definitely look into the nursery in Big Bear! That's a great idea for a service! Thanks!

 

[Bonsai Nut]

Julian would work as well, though it's a little lower elevation and doesn't get quite as cold (depending where you are in both areas).

I wish you luck. One of my big challenges in SoCal was wanting to keep certain cold hardy species that couldn't take the lack of cold (bristlecone pine, Japanese maple, many oak species, etc).

 

[Paradox]

If people can grow Southern California-native junipers in Minnesota, or the Mid-West, or anywhere where it snows in the winter...we here in Southern California should be able to grow trees that need a freezing cold winter. Or, at least, the creation of a colder winter should allow us here to grow healthier Japanese maples (or other PNW climate-adapted trees). Has anyone (engineers by profession maybe?) built a "cold room" for trees? Has anyone modified air conditioning units, for example, to create something like a cold mat? Blocks of ice are impractical (they would melt)...I was thinking creative uses of refrigerants (Freon, etc.)... I'm just curious what people have come up with...

It is a lot easier to protect a warmer species in a colder climate (provide greater protection during winter), than try to provide cold in a area that doesnt get cold in the winter. Unless you want to spend tons of money on building a refrigerated room. An air conditioner wont lower the temperature low enough. You need to be below 40 deg F for a very long time for proper dormancy.

For example, many of us in the north keep tropicals and we bring them inside the warm house during the winter.
I would never be able to keep a species that requires a much colder winter than my area has. Spending lots of electricity on a cold room would be cost prohibitive.

If its only one tree you could try a dedicated refridgerator

 

[Wattsy]

When I was brewing beer I used a refrigerator with a cheap control unit as fermentation chamber you could use the same controllers to regulate the temps of chest freezer install a n exhaust fan and put them in the freezer maybe some led lamps to slowly bring them into spring season I am sure that would work but only for a few trees unless of course you had multiple freezers

 

[Srt8madness]

I've come to the conclusion that zone envy just wastes money. I've killed enough cold weather species. The hots are too hot, and the lack of frigid cold just makes them even weaker and more susceptible to the heat. It's a cycle to death

 

[rockm]

I have seen numerous threads on this forum that deal with how to handle trees in the winter, in colder zones -- i.e. threads on how to prevent roots from freezing. This includes the creation of special rooms or growhouses, and/or complete overhauls of existing rooms such as garages. In some of these threads I've seen members of this forum get very creative with their intricate modifications (heat mats, instead of carpet, that are on timers, etc.). But, as far as I can tell, these types of threads -- where people get very creative in "controlling" nature -- deal with making extreme cold climates tolerable for trees that aren't used to such coldness. And when people do discuss warmer modifications for extreme heat, the solution is always the introduction of increasing levels of shade cloth and misting. (I was out watering my "full sun" junipers today and noticed that it was so hot, transpiration was hardly taking place, and, when shaded, the high heat remained and the non-evaporating water was probably just stimulating the growth of dangerous mold.)

Anyway, my main concern here is the complete non-existence of winter where I live (Southern California). And I know people on here can come up with some pretty crazy, probably excessive, far out there designs for rooms built to control or reconfigure nature. If people can grow Southern California-native junipers in Minnesota, or the Mid-West, or anywhere where it snows in the winter...we here in Southern California should be able to grow trees that need a freezing cold winter. Or, at least, the creation of a colder winter should allow us here to grow healthier Japanese maples (or other PNW climate-adapted trees). Has anyone (engineers by profession maybe?) built a "cold room" for trees? Has anyone modified air conditioning units, for example, to create something like a cold mat? Blocks of ice are impractical (they would melt)...I was thinking creative uses of refrigerants (Freon, etc.)... I'm just curious what people have come up with...

Trying to "create" a cold environment for colder weather species is mostly a fool's errand. The dormancy process is a lot more than just cold weather (and FWIW, roots SHOULD freeze in most overwintering situations--the trick is to keep temps from going TOO far below freezing).

Climate envy in bonsai runs both ways, there are folks in cold zones that Jones for tropicals and those in warm zones that want to keep maples. Both find a lot of difficulties--although tropical species fare a lot better in modified climates than temperate zone species.

Inevitably the "successful" people developing ways to keep trees cold, is a simple refrigerator. "Success" is a relative term. Most everything I've seen treated that way is only "meh" to really bad (as in the "why bother" zone)...I've also not seen anyone who has kept trees with that method have any sustained "success' beyond a few years. There will probably be posts to prove me wrong, but I'd guess the meh and why bother? categories are the norm.

Most sensible and satisfying solution is to skip the envy and deal with species native to your climate. If I lived in So. Cal, you bet Id have collected Cali junipers, pomegranates and Redwoods. I know I cannot keep any of those successfully in my climate. I have been keeping Texas native trees for quite a while, but they are borderline hardy (zone 7) here. I store one, a collected old live oak, in a cold greenhouse at a nursery. Been doing that now for going on 25 years. It's not cheap and it's a hassle, but it's the price I shoulder to keep the tree healthy.

 

[It's Kev]

I’ve learned to stick with whatever suits my hardiness zone. I do have some tropicals but they aren’t really my thing. Mediterranean species work for me (within reason) and I don’t have to work too hard to mimic a particular environment

 

[BobbyLane]

Trying to "create" a cold environment for colder weather species is mostly a fool's errand. The dormancy process is a lot more than just cold weather (and FWIW, roots SHOULD freeze in most overwintering situations--the trick is to keep temps from going TOO far below freezing).

Climate envy in bonsai runs both ways, there are folks in cold zones that Jones for tropicals and those in warm zones that want to keep maples. Both find a lot of difficulties--although tropical species fare a lot better in modified climates than temperate zone species.

Inevitably the "successful" people developing ways to keep trees cold, is a simple refrigerator. "Success" is a relative term. Most everything I've seen treated that way is only "meh" to really bad (as in the "why bother" zone)...I've also not seen anyone who has kept trees with that method have any sustained "success' beyond a few years. There will probably be posts to prove me wrong, but I'd guess the meh and why bother? categories are the norm.

Most sensible and satisfying solution is to skip the envy and deal with species native to your climate. If I lived in So. Cal, you bet Id have collected Cali junipers, pomegranates and Redwoods. I know I cannot keep any of those successfully in my climate. I have been keeping Texas native trees for quite a while, but they are borderline hardy (zone 7) here. I store one, a collected old live oak, in a cold greenhouse at a nursery. Been doing that now for going on 25 years. It's not cheap and it's a hassle, but it's the price I shoulder to keep the tree healthy.

Think you have to have an appreciation for nature. many in the hobby dont, and most if not all inspiration is drawn from looking at pictures of bonsai trees.

 

[Clicio]

I don´t even try to grow White pines here in the tropics.
But Red pines, Black pines, Shimpaku and some maples - specially Trident Maples - are doing very well and thriving, alongside BRTs, Jaboticabas, Elms and Prunus (Mume, Glandulosa, Serrulata).
I will be going against most people here, but I´ve found that the trees do adapt, and yes, most japanese and temperate species go dormant, lose their leaves, wake up in Spring and grow.
My main concern here is NOT the Winter, but the Summer.
They all need protection from the sun and heat in high summer (here around January-February). Maples go all under shade and protected from the wind, Junipers and Pines sit happily under the sun, but ALL OF THEM get watered from two to three times a day. Junipers like to be misted as many times as possible.

All my plants are outdoors at all times, including Ficus in the winter and maples in the summer.
They are in a location colder than São Paulo, by the mountains; it helps a little.

 

[Leo in N E Illinois]

@Emanon - most winter hardy trees can have their chill requirements met with being held at a temperature between 32 to 45 F for a period of 12 weeks. Some species like larch MUST have temperature colder than 38 F. Some species that do not need as sharp a dormancy, pomegranate or Satsuki azalea for example.

When I ran a blueberry farm, sold my share a few years ago, retired for the second time, I saw an interesting trick used by my organic berry broker. For best shelf life, blueberries need to be chilled to 33 to 35 F within 4 hours of being picked. Miss that and what you picked for the day will go to mush in a week or less. If you chill your blueberries right away after picking them, your berries will be saleable in a Whole Foods or Fresh Market for 3 or 4 weeks. Big $$$ incentive to get berries chilled quickly when picking. We were running a small "no spray", "no chemicals at all", organic operation. When pickers were picking we had one person making hourly run to the refrigerated storage area in the brokers pole barn. Our broker also leased space in a refrigerated warehouse, much like what a grocery store would use. But this was a distance away, so he would gather small loads of berries at his pole barn until he had a truck load to run to the warehouse.

Our broker had constructed a room just big enough for 3 pallets on the floor and room for one skinny worker to walk around them. It was framed with 2 x 4's inside a much larger pole barn and insulated with R-12 fiberglass. He took an ordinary 1500 BTU window air condition, removed, or rather hot wired around the thermostat and wired in a internet purchased controller that allowed him to adjust the thermostat of the air conditioner so that it would cool the room to 33 F. Actually, like a furnace thermostat the one he wired in was wall mounted about 8 feet away from the air conditioner unit. It worked fine. Chilled the room and did not cost more than an air conditioner to run. It took investigation on his part to figure out how to hot wire an air conditioner, but it could be done.

Now you would not need to be as precise as 33 F. You should decide what species you want to winterize. For example Japanese Black Pine winterize nicely with 12 weeks of 40 F. maybe even as warm as 45 F.

Some species will want it a touch colder, some warmer, but most will be fine with 12 weeks at 38 to 42 F , a little lumber, a little insulation, a fan for air circulation, an air conditioner, a little "hot wiring" and you could do it. The internet is your friend. Look at DYI cold storage, for fruit growers.

 

[Leo in N E Illinois]

I don´t even try to grow White pines here in the tropics.
But Red pines, Black pines, Shimpaku and some maples - specially Trident Maples - are doing very well and thriving, alongside BRTs, Jaboticabas, Elms and Prunus (Mume, Glandulosa, Serrulata).
I will be going against most people here, but I´ve found that the trees do adapt, and yes, most japanese and temperate species go dormant, lose their leaves, wake up in Spring and grow.
My main concern here is NOT the Winter, but the Summer.
They all need protection from the sun and heat in high summer (here around January-February). Maples go all under shade and protected from the wind, Junipers and Pines sit happily under the sun, but ALL OF THEM get watered from two to three times a day. Junipers like to be misted as many times as possible.

All my plants are outdoors at all times, including Ficus in the winter and maples in the summer.
They are in a location colder than São Paulo, by the mountains; it helps a little.

Embrace what Clicio says, he has hands on experience, I don't. I have to work to keep my trees warm in winter.