When to winterize

[Vinnie Charity]

It completely depends on what species your keeping and the climate you have. I'm not familiar with Richmond but would imagine it's usda zone would be 7... typical winter lows in the single digits approaching 0 F... that's similar to mine here in GA. Keeping my cold hardy trees on the ground and out of the wind and sun when frozen is pretty much all I do. For prolonged cold in the teens or colder, mulching with wood chips would be a good idea. Newer folks tend to over complicate their winter protection plans/overprotect their trees during the winter which leads to issues with drying out or breaking dormancy too early.

Some of my larger trees will be going under their benches and the benches will be wrapped in thick plastic or be surrounded by "walls" made from cinder blocks that I stack around them, still trying to figure that one out. I might have to keep them in my workshop, which is not ideal for my workshop, but would be ideal for the trees. I need a shed...(sigh)

 

[Vinnie Charity]

What he ?said. I moved stuff in and out day after day last spring and lost my 3 best trees.

The first outdoor trees I got were obtained this February/March and consisted of a Juniper (doing well), a Chinese Elm (also doing well), and 3 Hornbeams. The crazy early Spring that we had killed all 3 of the Hornbeams, I think that wind was the culprit. They would have been my best 3 trees and were given to me by one of the club members here in Richmond...

 

[Dav4]

Some of my larger trees will be going under their benches and the benches will be wrapped in thick plastic or be surrounded by "walls" made from cinder blocks that I stack around them, still trying to figure that one out. I might have to keep them in my workshop, which is not ideal for my workshop, but would be ideal for the trees. I need a shed...(sigh)

If you're going to cover benches with plastic, make sure it's the heavy white, completely opaque type... anything clear or translucent will allow too much heat gain during sunny days, even in the dead of winter.

 

[Vinnie Charity]

If you're going to cover benches with plastic, make sure it's the heavy white, completely opaque type... anything clear or translucent will allow too much heat gain during sunny days, even in the dead of winter.

The tops will have openings in them, basically the spaces between the boards, do you think the clear plastic would still heat up the interior? This is my first time overwintering trees so I'm trying to get all of the advice I can...

 

[JudyB]

The tops will have openings in them, basically the spaces between the boards, do you think the clear plastic would still heat up the interior? This is my first time overwintering trees so I'm trying to get all of the advice I can...

Yes, like I said earlier, sun will make it too hot in there and you may cook your trees. Dormant trees don't need sun, and it just causes heat issues.

 

[jimib]

This is my little greenhouse. The top isn’t clear like the sides are. Where it sits it gets full sun until late afternoon. When the temperature is in the high 70s to low 80s, it gets 100° or more in there, even with the vent open. In the winter, it still gets 15 to 20° warmer in there when the sun is out. Currently I have 50% shade cloth running up the inside panels.Now I’m considering using a white tarp over the whole thing for the winter to keep the temperature low.

 

[Vinnie Charity]

Yes, like I said earlier, sun will make it too hot in there and you may cook your trees. Dormant trees don't need sun, and it just causes heat issues.

Got it, back to the drawing board, lol. I'm doing more research when I should be working, but it's Friday, my trees are important, and there's less than a month before I put them up for the winter.

I have quite a few trees in my collection, some are in nursery pots, and some are in nice Bonsai pots...

(currently in nursery pots)
I have about 5-6 Bald Cypress, an Azalea , a River Birch, 1 Juniper, 5 Japanese Maples (1 very tall and one Mame), 2 Dwarf Alberta Spruces, a Yew, a Chinese Elm (in a flat), an Eastern Red Cedar, a Shimpaku Juniper, 3 different kinds of Boxwoods, 1 Field Maple, 1 Trident Maple,

(currently in Bonsai pots)
3 Junipers

All of the Bald Cypress trees, the Eastern Red Cedar, 1 of the Japanese Maples and the Trident Maple are all pretty tall (3-5 tall), but the other trees are all around a foot tall or shorter.

My growing area is a 10' x 10' concrete slab that is about 2 feet from the side of my house (not where the roof slants). The benches are all around the slab and the slab is surrounded by grass. The walkway is connected to my rear driveway, as seen in the picture below...



Hopefully this helps in better understanding my situation as I would like a simple, repeatable method for overwintering my trees. Thanks to everyone that shot down my "bad" ideas, and as always, any advice is much appreciated.

 

[Vinnie Charity]

Maybe surrounding the trees with the cinder blocks and covering them with the boards would work? I have a TON of cinder blocks...

 

[rockm]

This is something I'm doing more research on as well.

This will be my first time having outdoor bonsai and I would like them all to be alive next Spring. I've been fertilizing them like crazy and they are all pretty healthy.

I applied the last fertilizer at the beginning of the month and haven't applied anymore since.

I'm planning to build cold frames out of the cinder blocks and boards that I use for benches (sort of convertible benches ), and I have windows to put on top to protect them.

What do the pros think?

You do NOT need the windows on top. They will push late winter temps underneath in the cold frame to unacceptably high levels and then you will have trees in leaf in Jan. or early Feb. Not a good situation at all. Best thing to do in these parts is to SHADE your winter storage area. Ensure it does not get direct sunlight that will warm the ground/mulch pots, etc.

The thing about winter storage that many beginners get wrong is their assumption that they're keeping trees "warm." far from it. Doing that is a death sentence for them. What you are trying to do is to keep them as cold as possible FOR AS LONG AS POSSIBLE before they finally break dormancy. This last part is very very tricky here in Va. Overprotection is a preventable problem.

I keep almost all of my trees, including many Texas native species in the backyard on the patio, mulched over with eight or nine inches of mulch. I keep others in a two foot deep cold frame with foot and a half tall walls that is covered by 1x4 boards to completely shade the interior. That shade is very important come late Jan. early Feb, when the sun can warm the ground quickly and deeply. that is NOT what you want.

Also, I would not adhere to a strict schedule to put them away. We're at least two weeks behind on dormancy here because of the warm early October weather. The forecast for the next couple of weeks has no frost in it. Not a good thing. I'm probably going to BEGIN putting trees away come Thanksgiving, but if the forecast doesn't change, I'm not going to rush to get them into storage.

 

[Vinnie Charity]

You do NOT need the windows on top. They will push late winter temps underneath in the cold frame to unacceptably high levels and then you will have trees in leaf in Jan. or early Feb. Not a good situation at all. Best thing to do in these parts is to SHADE your winter storage area. Ensure it does not get direct sunlight that will warm the ground/mulch pots, etc.

The thing about winter storage that many beginners get wrong is their assumption that they're keeping trees "warm." far from it. Doing that is a death sentence for them. What you are trying to do is to keep them as cold as possible FOR AS LONG AS POSSIBLE before they finally break dormancy. This last part is very very tricky here in Va. Overprotection is a preventable problem.

I keep almost all of my trees, including many Texas native species in the backyard on the patio, mulched over with eight or nine inches of mulch. I keep others in a two foot deep cold frame with foot and a half tall walls that is covered by 1x4 boards to completely shade the interior. That shade is very important come late Jan. early Feb, when the sun can warm the ground quickly and deeply. that is NOT what you want.

Also, I would not adhere to a strict schedule to put them away. We're at least two weeks behind on dormancy here because of the warm early October weather. The forecast for the next couple of weeks has no frost in it. Not a good thing. I'm probably going to BEGIN putting trees away come Thanksgiving, but if the forecast doesn't change, I'm not going to rush to get them into storage.

I fully understand that they trees need to be kept cold, I'm just trying to think of a way of doing that while keeping the wind off of them and not using mulch. Do you think that stacking cinder blocks around all of the trees and covering these "frames" with boards would do the trick @rockm?

Thanks for all of the advice everyone...

 

[rockm]

I fully understand that they trees need to be kept cold, I'm just trying to think of a way of doing that while keeping the wind off of them and not using mulch. Do you think that stacking cinder blocks around all of the trees and covering these "frames" with boards would do the trick @rockm?

Thanks for all of the advice everyone...

Stacked cinder blocks covered with boards are inadequate
unfortunately if you don't cover the roots with something, all your other protections aren't going to do much good. Protecting the roots is the heart and soul of overwintering. Mulch is a must if you've got them outside. It buffers the worst low and high temps, as well as keeps moisture on the roots (wind and dry winter air will pretty quickly dessicate soil and roots --dry roots are EXTREMELY vulnerable to freezes).

.

 

[Vinnie Charity]

I feel like the evil genius that keeps getting his plans foiled by the good guy, lol.

You mulch up to the first branch I'm sure, and that will be a LOT of mulch. My only issue with mulch is the amount I would need to purchase and then figure out what to do with it next spring since I don't mulch my yard.

You said you have some trees in a 2 foot deep cold frame covered by boards. Do you mean 2 feet deep in the ground or just a 2 foot tall cold frame? The cinder block "boxes" I wanted to build would be about the same height and covered with boards as well, wouldn't that be the same thing?

 

[Vinnie Charity]

Do you also mulch the trees that are inside your cold frame @rockm? Looks like I'm going to have to invest in some mulch or find some pine tags in a large amount...

 

[Dav4]

The tops will have openings in them, basically the spaces between the boards, do you think the clear plastic would still heat up the interior? This is my first time overwintering trees so I'm trying to get all of the advice I can...

Yeah, lose the plastic wrap and get burlap... makes a great wind break and sun screen. Bunch the pots together, then apply mulch around, up and over the top of the pot up to the trunk.

 

[rockm]

Do you also mulch the trees that are inside your cold frame @rockm? Looks like I'm going to have to invest in some mulch or find some pine tags in a large amount...

Yes I do. The idea of mulch is to trap "heat" or at least warmer relative ground temperatures and even the root zone temperature out. A cold frame by itself isn't going to do that very well without mulch. Another thing to keep in mind is that cold air acts much like water, it "flows" downhill and collects in low spots. Putting a cold frame on a slope can keep it warmer relative to other lower areas in the yard.

My "cold frame" is really a "cold pit" that is sunken two feet into the ground. That lower profile helps a bit because the surrounding earth is slower to warm up or cool down that the ground surface.

 

[rockm]

Yeah, lose the plastic wrap and get burlap... makes a great wind break and sun screen. Bunch the pots together, then apply mulch around, up and over the top of the pot up to the trunk.

Plastic is NOT your overwintering or frost protection friend. It will kill branches that come in contact with it, as it traps moisture and condensation completely on its underside. If a branch comes in contact with that moisture it get frozen solid and die back can result.

 

[Vinnie Charity]

Looks like I'm going to be buying some mulch then @rockm, and I'm glad to see you are in Virginia as well. One of the guys in my bonsai society here in Richmond recommended using leaves, which I will have PLENTY of this fall.

I'll build my cinder block fortress and fill it with mulch or leaves and hopefully that will do the trick.

Thanks again for all of your advice...

 

[rockm]

Looks like I'm going to be buying some mulch then @rockm, and I'm glad to see you are in Virginia as well. One of the guys in my bonsai society here in Richmond recommended using leaves, which I will have PLENTY of this fall.

I'll build my cinder block fortress and fill it with mulch or leaves and hopefully that will do the trick.

Thanks again for all of your advice...

I wouldn't use leaves...Not enough protection. They also tend to get flattened out and their insulating properties are largely lost when it rains/snows....C'mon mulch is $2 for a 35 lb bag...

 

[Vinnie Charity]

Haha, and where do you get your mulch @rockm? Guess I'll be heading out to Home Depot this weekend to stock up on mulch, $3 a bag isn't too bad...

 

[rockm]

Haha, and where do you get your mulch @rockm? Guess I'll be heading out to Home Depot this weekend to stock up on mulch, $3 a bag isn't too bad...

You can get it on sale in the summer ;-) I typically get eight bags of it. I have about two dozen large trees.

Forgot to mention a very important thing--when you put your trees on the ground inside the shelter, make sure the feet are placed on bricks on the ground. THEN mulch them up. The air space provided by the bricks between the bottom of the pot and the ground provides an airspace so the pot can drain. Placing the pots directly on the ground is a recipe for a swamp in your pots over the winter and associated root death.