LOL. It's actually quite helpful to know location. FWIW, don't take offense to anything said on Bnuts. Opinions are like belly buttons, and some of us have cranky belly buttons. We ask for opinions here and folks will surely give them.
Japanese Maple in Minnesota Winter (USDA Zone 4a)
- Thread starter turnyface
- Start date
Grunge_Bonsai
Yamadori
This is true. I am going to meditate on my own cranky belly button. 
In all seriousness, it’s cool how it works and shows relevant info when users post.
In all seriousness, it’s cool how it works and shows relevant info when users post.
Gabler
Masterpiece
Bonsai is like real estate. Location; location; location.
Ininaatigoons
Shohin
Greetings from Minnesota!
Lots of info so far. I've done wintering of Japanese Maples for years now. Attached garage is OK most of the time. Two major things to remember. Keep a thermometer and eye on it to make sure Temps stay warm enough. I actually have to heat the garage a couple nights a year when it's -15 or so. The other major point is keep off the ground. Mine are on a shelf 7' off the ground. It stays warmer up there plus just think every time you open the garage door all that outside air floods in and anything low gets hit. Lastly water. Make sure they are moist going in and stay that way. You ever notice how fast that slush pile that drops off your car evaporates? Finger check moisture often.
Now to answer the original question. Take inside when nights are around 20 and in the spring you must do the dance. I guess Japanese Maples don't do well after they have seen warmer temperatures. When the sap starts flowing they have lost most of their hardiness and will check out if they go back under freezing. Spring frosts are deadly to Japanese Maples in pots.
Do not collect more trees than you want to move back and forth a lot in the spring. I have too many and it is almost too much work.
On YouTube is Dave's Bonsai. He's another crazy Minnesotan dealing with trying to grow Japanese Maples and other exotics as bonsai. Make sure to check him out.
Lots of info so far. I've done wintering of Japanese Maples for years now. Attached garage is OK most of the time. Two major things to remember. Keep a thermometer and eye on it to make sure Temps stay warm enough. I actually have to heat the garage a couple nights a year when it's -15 or so. The other major point is keep off the ground. Mine are on a shelf 7' off the ground. It stays warmer up there plus just think every time you open the garage door all that outside air floods in and anything low gets hit. Lastly water. Make sure they are moist going in and stay that way. You ever notice how fast that slush pile that drops off your car evaporates? Finger check moisture often.
Now to answer the original question. Take inside when nights are around 20 and in the spring you must do the dance. I guess Japanese Maples don't do well after they have seen warmer temperatures. When the sap starts flowing they have lost most of their hardiness and will check out if they go back under freezing. Spring frosts are deadly to Japanese Maples in pots.
Do not collect more trees than you want to move back and forth a lot in the spring. I have too many and it is almost too much work.
On YouTube is Dave's Bonsai. He's another crazy Minnesotan dealing with trying to grow Japanese Maples and other exotics as bonsai. Make sure to check him out.
turnyface
Yamadori
Great info, thank you!
Paradox
Marine Bonsologist
Location gives us an indication about your weather. In a country as large as the US, the weather on one side of the country is very different from another. Plants respond to weather, it is a very important factor in their physiology and growth. So yes, it really helps us to give the best advice.
Plants wake up in the spring much earlier in the south (ie warm areas) than up north (cold). The timing of many things we do in bonsai is based on the seasonal cycles of weather and tree physiology.
Grunge_Bonsai
Yamadori
Yes. This is why the site is so cool, anyway. I have already found advice from more experienced users who live in North Carolina — much more relevant experience to me, here in the middle Georgia Piedmont region, than someone who lives in the Midwest or west coast, for example.
Paradox
Marine Bonsologist
I live in NY. I always try to keep in mind where the person is when I give advice
turnyface
Yamadori
I appreciate all the info shared in this thread. I feel like I have a good game plan for this winter.
I’m now thinking of growing out this tree to make it a mother tree and create air layers in a few years for a bonsai. This current tree is grafted and would like to not have that on the final tree.
Is there an upper limit to the size of growth pot I can use? I see people using pond baskets, which I think will be the route I take next spring.
Is it safe to bare root the tree in the spring during repotting or should I keep some of the nursery soil around the root ball?
I’m thinking I’ll use a 1:1:1 mix of fine pine mulch, pumice, and Napa 8822 for the soil when I repot.
I’m now thinking of growing out this tree to make it a mother tree and create air layers in a few years for a bonsai. This current tree is grafted and would like to not have that on the final tree.
Is there an upper limit to the size of growth pot I can use? I see people using pond baskets, which I think will be the route I take next spring.
Is it safe to bare root the tree in the spring during repotting or should I keep some of the nursery soil around the root ball?
I’m thinking I’ll use a 1:1:1 mix of fine pine mulch, pumice, and Napa 8822 for the soil when I repot.
rockm
Spuds Moyogi
"Is there an upper limit to the size of growth pot I can use? I see people using pond baskets, which I think will be the route I take next spring."
There's a qualified no--the larger the empty space that is uncolonized by roots in a pot, the harder it will be to water. The extra space with no roots in larger containers tends to hold more water than the space with the roots-since the roots use the water. That extra wet space around a drier one can cause issues in rooting and development of a tree, sometimes leading to death by root rot or root drying out. Roots can also be reluctant to cross into soils that are different from the ones they're growing in. That means if the outer soil is wetter than the interior (or vice versa), roots will only circle around in the interior soil. That can also lead to problems
Bottom line, don't go larger than a third more than the existing root mass. Work your way to to larger containers as the root mass develops.
Paradox
Marine Bonsologist
I grew up about 20-30 minutes from Great Falls in Lewiston
Ininaatigoons
Shohin
If your growing out you should use a nursery can. Just a bit bigger than the current one. 4" to gallon, gallon to 3 gallon, 3 to 5 or 7.
Vorderbruggen
Seedling
St. Paul Minnesota here. I have some Japanese maples that will be going through their first Minnesota winter this year. I wish I had waited to repot mine. I would have built grow boxes. Grow boxes will be easier to insulate overwinter, and are built however you want them, so you can design it around the tree. I haven't tried this yet, but I had the thought that a grow box set inside a heavy duty cardboard box and then filled with leaves would allow me to easily move the insulated tree. The wide square flat bottom would be less prone to tipping or spilling in the cardboard box than a nursery pot or anything round. The mess made with leaves can stay in the yard when filling the box, and moved wherever you want to dump them out when the time comes. I'm always learning but that's where I'm at with it now.
Ininaatigoons
Shohin
I suggest tall nursery cans because they are easier to monitor water. Not too wet because the gravity pulls it down and out, not to dry because evaporation has to come from the smaller top and through the rest of the vertical soil. Flat pots mostly look cool and that's it. Water is harder to monitor especially if it's a flat bottom without incredible drainage. In a bonsai pot it just stays which is why the large particle soil is used.
So if your growing out and especially if your growing out for stock material I suggest the can.
So if your growing out and especially if your growing out for stock material I suggest the can.
turnyface
Yamadori
Ok, so larger nursery pot.
What about bare rooting?
What about bare rooting?
gschup
Sapling
Japanese Maples can handle quite substantial root reductions as well as bare-rooting, in my limited experience.
Gabler
Masterpiece
With rare exceptions, you shouldn't feel bad about bare rooting angiosperms (or ginkgoes).
Ininaatigoons
Shohin
Summer repot is always iffy. I wouldn't suggest a bareroot and especially not root cutting.
Gabler
Masterpiece
I think the plan is to repot in spring.
Similar threads
