Monterey Cypress cold winter conditions

Captain_Sensible

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Hi Everyone,

I'm new to this so any and all advice is appreciated (especially from anyone who has experience with this tree). A few months back I was given a Monterey Cypress seedling (2-3 years old). Most of my family lives in northern California and I was given it as a reminder of home. Which is great and I love this little tree. For the past few months it has been living and growing happily in a small (2x4 inch) bonsai pot. The problem is that I now live in eastern Pennsylvania and it is my understanding that in the winter temperatures drop below freezing for several days. From what I have read online these trees should never be exposed to freezing temperatures. So I am not sure what is best to do.

I have a detached non heated garage, I am considering insulating the pot in some way and placing it in the garage for the coldest 2 or so months. It will be protected from the wind but I think it will still get below freezing in the garage. If I go this route does anyone have any advice on how to insulate it? I am thinking mulch around the pot and base of the tree with burlap wrapped up to hold it in place but I have no idea how I should water it if its all wrapped up like this. One thing I am concerned about with this option is that it will receive very very very little light (if any) in the garage. Does that matter if it is dormant?

Should I bring it inside? I don't know how that may affect its dormancy period. I am not sure what type of dormancy these trees have. I could try to keep it in a room that may be colder than the rest of the house but I dont know yet how cold/warm that room may be.

I am in a new house in a new part of the country so there is a lot that I am not sure of what to expect. Any advice is greatly appreciated, I am happy to provide any additional info if needed.

Thanks all!
 

Forsoothe!

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If you click on your Icon in the upper right corner and add your location, people can give advice customized to your climate.
 

Leo in N E Illinois

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Monterey Cypress, Cupressus macrocarpa, or the most recent botanical name,Hesperocyparis macrocarpa , is from coastal California. If you recall where you've seen it in the wild, it is from areas where the roots never freeze, or rarely freeze to any significant depth. Your best bet for wintering this tree is finding a spot in your house that is as cool as possible and yet remains above freezing. Ideally if you can keep the temperature between 32 F and 40 F, or +0 C to +4 C, that would be ideal. If kept below 40 F, the location will not need light, as plant metabolism will be slow enough that the tree easily will survive a 4 month dark period. If the temperature gets above 40F even for a few hours a day, then you should have light. Depending on how cold your garage gets, or unheated shed gets, this may or may not work for you.

Alternately. Jack Wilke has demonstrated that one can keep Hesperocyparis pygmaea, in an underlights set up for many years. Jack grows his without putting them outdoors. I assume H. macrocarpa would perform very similar.

Many people have partially heated garages, where the temperatures are significantly cooler than indoors, but often are above 40 F, or 4 C. Here setting up an underlights set up would help. The main issue would be keeping on top of watering. The cooler the weather, the less frequent the watering, but you still may need to water. Ordinary fluorescent shop lights, or the LED shops lights, while not designed as "plant lights" are bright enough that in a relatively cool space they can limp even high light demanding trees through the winter. Key, as long as it is cooler than the typical household, but above freezing.

Keeping it above freezing has the benefit of freeze-thaw cycling will not break your bonsai pots. High quality bonsai pots are normally freeze resistant, but medium and lower quality pots often are not resistant. Keeping it above freezing will solve this issue.
 

Bonsai Nut

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You might be able to keep it outside. They are supposed to be cold hardy to zone 7, but you are just on the edge. Down here in Charlotte I'm right on the edge between zone 7B and 8A and I plan on leaving mine outside. Just keep it wet - mine drinks water like a camel.
 

sorce

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I wonder of Nature's Way rents overwintering grounds?

It's only 2 hours away. Worth the trip twice a year!

Welcome to Crazy!

Sorce
 

Captain_Sensible

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Thank you everyone for the responses!
You have definitely given me a lot to think about and helped me be a bit more optimistic about my options. I don't think any part of my house will be anywhere near 40 degrees F (but I will be sure to look into what Jack Wilke does and see if it may work for me) so for now I think it will be best to keep it in my garage... 2 more questions...

1. Does the idea of insulating the lower portion of the tree make any sense? I have seen some websites recommend it but some don't mention it at all. I guess I am hoping that if I can insulate it well enough (using any method) I can keep the roots above freezing even if temperatures in the garage get below freezing.

2. I do have a little oil space heater (the kind that looks like a mini radiator). I don't like the idea of running that constantly but if I set it low enough to keep the temp just below 40 would that be an option or could that create more issues than it would solve?

Thank you again for the quick and informative responses. I really appreciate it!
 

Bonsai Nut

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1. Does the idea of insulating the lower portion of the tree make any sense? I have seen some websites recommend it but some don't mention it at all. I guess I am hoping that if I can insulate it well enough (using any method) I can keep the roots above freezing even if temperatures in the garage get below freezing.

2. I do have a little oil space heater (the kind that looks like a mini radiator). I don't like the idea of running that constantly but if I set it low enough to keep the temp just below 40 would that be an option or could that create more issues than it would solve?

Sorry I didn't see this note earlier!

I think you are operating under the false impression that you should avoid freezing temps at all costs. Zone 7 means the tree should be able to handle night time lows of 0 to 5 degrees F (as an extreme). Cold hardy trees have numerous ways that they have adapted to be able to handle cold and freezing temps (and are both good at freeze tolerance and freeze avoidance). Soil in a bonsai pot can freeze solid - and yet the roots can still remain unfrozen even as temps creep as low as -20F. You are far less likely to lose a Zone 7 tree to 20 degree temps than you are to lose it to temperature SWINGS. Trees go into and come out of winter dormancy slowly (over the course of months). Trees that can handle very low temps on average can be killed by an early deep freeze, or a late arctic blast in the spring as they have already started to wake up.

Also, many cold hardy trees not only have adapted to cold, but they NEED it in order to survive. Be careful that you don't shelter a cold hardy tree so much that you kill it with warmth. By keeping it in a 40F heated garage, you are basically saying "I am going to keep this Zone 7 tree in a Zone 10 environment. If it is a Japanese white pine (for example) you will kill it.

(1) Insulating the POT makes sense to the extent that it slows down swings of temperatures. You can understand how a pot on a bench sitting out in the sun and wind experiences more dramatic temp swings than the same pot sitting on the ground. Many people will take their trees (pot and all) and simply set them on the ground under their bonsai bench, and bank mulch around and over the top of the pots. If you do this it is important that you DON'T bury the trunk or the branches - which can sit out in the cold without protection. Snow is an excellent insulator, and it is fine for your trees to be buried under 12" of snow. It will not only protect your tree from the wind, but provide humidity.

(2) Unless you expect the temperature in your unheated storage space (garage, greenhouse, cold frame, etc) to drop below 0 F for extended periods, there is no reason to heat it to moderate the temperature. And if you do heat it, you want to make sure you don't heat it above freezing! You may inadvertently start to wake your trees up, and then when you turn off the heater, you will kill them. An unheated attached garage will probably be 10 degrees or more warmer than ambient temps, in addition to being protected from wind. A cold frame against the side of a house uses the shelter of the house as well as ambient heat from the ground to achieve the same result. Just make sure to put your cold frame on the north side of the house so you don't bake your trees on a sunny day!
 

Captain_Sensible

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Sorry I didn't see this note earlier!

I think you are operating under the false impression that you should avoid freezing temps at all costs. Zone 7 means the tree should be able to handle night time lows of 0 to 5 degrees F (as an extreme). Cold hardy trees have numerous ways that they have adapted to be able to handle cold and freezing temps (and are both good at freeze tolerance and freeze avoidance). Soil in a bonsai pot can freeze solid - and yet the roots can still remain unfrozen even as temps creep as low as -20F. You are far less likely to lose a Zone 7 tree to 20 degree temps than you are to lose it to temperature SWINGS. Trees go into and come out of winter dormancy slowly (over the course of months). Trees that can handle very low temps on average can be killed by an early deep freeze, or a late arctic blast in the spring as they have already started to wake up.

Also, many cold hardy trees not only have adapted to cold, but they NEED it in order to survive. Be careful that you don't shelter a cold hardy tree so much that you kill it with warmth. By keeping it in a 40F heated garage, you are basically saying "I am going to keep this Zone 7 tree in a Zone 10 environment. If it is a Japanese white pine (for example) you will kill it.

(1) Insulating the POT makes sense to the extent that it slows down swings of temperatures. You can understand how a pot on a bench sitting out in the sun and wind experiences more dramatic temp swings than the same pot sitting on the ground. Many people will take their trees (pot and all) and simply set them on the ground under their bonsai bench, and bank mulch around and over the top of the pots. If you do this it is important that you DON'T bury the trunk or the branches - which can sit out in the cold without protection. Snow is an excellent insulator, and it is fine for your trees to be buried under 12" of snow. It will not only protect your tree from the wind, but provide humidity.

(2) Unless you expect the temperature in your unheated storage space (garage, greenhouse, cold frame, etc) to drop below 0 F for extended periods, there is no reason to heat it to moderate the temperature. And if you do heat it, you want to make sure you don't heat it above freezing! You may inadvertently start to wake your trees up, and then when you turn off the heater, you will kill them. An unheated attached garage will probably be 10 degrees or more warmer than ambient temps, in addition to being protected from wind. A cold frame against the side of a house uses the shelter of the house as well as ambient heat from the ground to achieve the same result. Just make sure to put your cold frame on the north side of the house so you don't bake your trees on a sunny day!

This is very helpful information. Thank you so much. I had started building a cold frame and had planned on insulating the pot with soil and mulch. So it sounds like that is still a good route to go. I had purchased a little soil heating wire type of thing but now I will opt out of using this and rely on the cold frame and insulating the pot.
If the outside temp gets above 40 F I may let my tree get a little sun as a previous poster said they could use a little sun in temps above 40 F. If that sounds like a bad idea please let me know.
Thank you again for your informative post. I truly appreciate it!
 

Forsoothe!

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A cold frame can be made out of anything. Here's one made from 4" thick Styrofoam bats glued to home construction insulation board that has an aluminum skin for good weathering. The roof is slanted to shed snow and the reflective surface keeps the interior cool. All the components were flat for ease of summer storage. It was always on the sunny side of the house and the top removed when appropriate on spring days to introduce warmth & sunshine. Easier to use than a glass top.
41 First roof panel.JPG
46 All 3 plastic panels in-place.JPG
 

Captain_Sensible

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A cold frame can be made out of anything. Here's one made from 4" thick Styrofoam bats glued to home construction insulation board that has an aluminum skin for good weathering. The roof is slanted to shed snow and the reflective surface keeps the interior cool. All the components were flat for ease of summer storage. It was always on the sunny side of the house and the top removed when appropriate on spring days to introduce warmth & sunshine. Easier to use than a glass top.
View attachment 332980
View attachment 332981
Sorry for the late reply.
Thanks for the info and pictures! Always helps to see what has worked for other people. I ended up building mine out of styrofoam and plywood. I got soil and mulch to insulate the pot with and an led grow light if it gets above 40 and I cant "safely" get sunlight to my tree.
Thanks again for the help. This is a surprisingly helpful community on this board.
 

rollwithak

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Let’s see your little guy! I’ve recently grown some
Indoors and am having great success. I’m going to be more concerned with the opposite end of the spectrum in my zone, the heat!!! These guys are just a little over 3 months old!!!
 

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