Author Topic: cold climate, overwintering air layer questions  (Read 7618 times)

sdonny

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cold climate, overwintering air layer questions
« on: September 09, 2014, 09:45 PM »
I live in a cold climate (New Hampshire).  When the buds were coming out in April, I started several layers on the Japanese red maple in my yard.  I kept the spaghnum moss moist all Spring and Summer.  There were roots starting to show through the moss in August but not enough to chop and transplant to the ground before Winter.  Now, in mid-September, there are enough roots, but there is not enough time for the new roots to establish and harden before the ground freezes.  I plan on chopping the air layers off before the first frost and pot them in my unheated greenroom where it stays above freezing throughout the winter (however temps sometimes fluctuate up into the 60s on hot days).  My thoughts are they will go into a dormant state until Spring out in the greenroom.  However, I'm not sure of the best way to help these air layers maintain moisture in this space and how much of an issue the temp fluctuations will be.  Any suggestions or advice on overwintering air layers in cold climates is appreciated.  Terrariums?  Plastic?  Leaf removal? 

Also, the leaves are starting to turn and since they will most likely all fall off on their own...my second question is how much of the branches and leaves should/can I remove to get the layers into more manageable sizes to pot or fit into a terrarium for winter?  Branches range from 1/2 to 2" in diameter and 3-5 feet past the air layers.  It seems to be impractical to insulate up in the tree and from past experience, the air layered roots when left unprotected have frozen over the winter and died.  Thanks in advance.
 

Sorce

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Re: cold climate, overwintering air layer questions
« Reply #1 on: September 10, 2014, 06:03 AM »
I wouldnt put them in a terrarium. Probly not good.

Id leave some on, maybe a little styrofoam cooler will work.

And take some off. Pots on the ground, or in the ground. Or both of you have that many!

Good luck!

Sorce
 

Judy

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Re: cold climate, overwintering air layer questions
« Reply #2 on: September 10, 2014, 07:57 AM »
If you could find a way to protect them but still allow dormancy, that would be your best bet.  Fall is a great time for root development, so if they are ready now, I'd get them off the tree, so they can have that time to grow and adapt.  Then find a way to keep them from freezing (the roots) like with a heat mat, or buried heat cable, and allow the tree dormancy thru the winter.
 

Leo in NE Illinois

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Re: cold climate, overwintering air layer questions
« Reply #3 on: September 10, 2014, 10:40 AM »
Your unheated green room could be used. Pot the cuttings up into pots now. They need time for the roots to harden off for winter dormancy. Ideally you should have taken your air layers off 8 to 12 weeks before your average first frost. I do understand that the roots did not develop right away, so you just have to work with what you have. Pot them up and keep them outside until the leaves change and fall. Definitely keep the air layers outside until fully dormant. Then bring them into your unheated green room. Put them in a cool and shaded corner, on the floor (heat rises) to avoid as much as possible the heat of 60 F on sunny days. If they begin growing before it is safe to put them outside in spring, move them to the brightest spot possible. Growth indoors will be weaker than growth outdoors in full sun, but there will be little you can do about that.

When you move the trees out in spring, if they have a lot of weak growth you will have to prune that off and let the trees send out a second flush of growth.

Are these air layers of named cultivars. If they are that is great. We don't see enough named cultivars of maples on their own roots.
 

bwaynef

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Re: cold climate, overwintering air layer questions
« Reply #4 on: September 10, 2014, 10:58 AM »
Judy has given good advice.  I'd wait til the leaves have changed and reduce the branches to manageable then, ...when pruning shouldn't induce growth that will be killed and weaken the plant.
 

Dave Murphy

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Re: cold climate, overwintering air layer questions
« Reply #5 on: September 10, 2014, 09:10 PM »
I've separated palmatum layers in zone 6 MA in early September, potted them up, and over wintered them with my other trees.  They did fine,  and spent the winter frozen under a layer of mulch.  If you have enough roots, separate now, then protect them well for winter, but don't baby them either...my 0.02.
« Last Edit: September 10, 2014, 09:12 PM by Dave Murphy »
 

Chrisl

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Re: cold climate, overwintering air layer questions
« Reply #6 on: September 11, 2014, 11:01 AM »
Do you all know if I take a layer in late Sept to mid Oct (I left stupidly the parent tree in the same spot it was located in the backyard, in the shade.  So the layer really wasn't moving, not even callousing over.  So I moved it into full sun a couple weeks ago.

Plan is to winterize the parent tree in my hoop house.  My question is, if I do get roots later this yr., are these going to get thru the winter if I put them into the ground?

Thanks....can't believe we're talking about damned winter already!! ;((
 

Leo in NE Illinois

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Re: cold climate, overwintering air layer questions
« Reply #7 on: September 11, 2014, 06:37 PM »
I don't know about maples, the few times I attempted air layers, I did it in spring and was able to separate them by middle of August. But my few (2 successes, one failure) experiences with air layering JBP it always took 2 years to get roots to form. I just wintered the JBP in the same way I always did - which was to put them in my unheated well house. They stayed outside until temps were below freezing regularly at night. They went into the well house only after a few night time lows of 25 F.

I don't think freezing will kill the roots of an air layer- though freeze thaw cycles may kill them. If they can be situated where they freeze once and stay frozen, they will probably be fine.
 

Dave Murphy

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Re: cold climate, overwintering air layer questions
« Reply #8 on: September 11, 2014, 07:40 PM »
The roots will die if the intracellular water in them freezes...the temperature where this occurs varies from species to species.  The rule of thumb is that roots need to be protected if the air temps fall into the mid teens or below.  If it gets cold enough, the layer roots will die.
 

Chrisl

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Re: cold climate, overwintering air layer questions
« Reply #9 on: September 12, 2014, 10:01 AM »
Leo, no way to keep the layer from freezing.  I just don't have that fine control over the weather w. a 1500wt heater.

That's what I was thinking too Dave, very tender roots.  Given, if I don't get roots this yr. I'm just going to put the whole bloody tree back in the ground leaving the roots mass in the pumice.  And then try again next yr.  I'm pretty sure I'm going to have to do this, it was 53F yest and supposed to be in the low 60's for next 7-10dys.  I missed summer and our fall is looking sketchy.  So weird weather is simply NOT helping lol
 

Leo in NE Illinois

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Re: cold climate, overwintering air layer questions
« Reply #10 on: September 16, 2014, 11:10 AM »
It is a good thing we are not depending on bonsai paying the mortgage and putting food on the table.

Quite honestly, I don't have enough experience to really know. My pine air layers didn't mind temps into the 20's, they took 2 years to develop roots. In all likelyhood going into the first winter there was only callus on the air layer.

The weather this year has "screwed" us. The late cold spring really retarded everything around here - did not get my first tomatoes until the last week of August. Some years we win, some we loose - this one was bad.

I'd just follow Dave's initial advise - harvest the air layers, pot them up, bury the pots in the ground where you normally winter your maples and cross your fingers. Maybe they will make it, maybe not.

Right now the cold wave is supposed to end for a while, maybe there will be time for roots to harden off before the first frost. One can hope, eh?
 

0soyoung

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Re: cold climate, overwintering air layer questions
« Reply #11 on: September 16, 2014, 12:51 PM »
Logically, the layer roots will be okay in the ground - because it is an explant from a tree in your yard (=planted in ground). But you can also heap a little extra mulch over the base of the explant for a little extra insulation.

A key issue will be to stabilize the tree so the layer's roots won't be broken. When I harvest larger layers, I leave the roots and wad of sphagnum intact - just remove the covering. I drive a screw through the bottom of a plastic pot into the cut end of the stem. I also have one or two bamboo poles screwed to the pot sides to 'stake' the tree.

I fill the pot with Turface MVP because I get the fastest root growth - far better than in garden soil. I presume most any bonsai medium will be similar. You could do likewise and sink the pot in the ground for the winter.

Let the normal leaf drop process proceed if the explant's leafs are not dessicating. If they are abnormally drying, you may be better off defoliating. All other things being equal, I prefer to wait until spring to prune - some amount of die-back is inevitable.
 

Chrisl

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Re: cold climate, overwintering air layer questions
« Reply #12 on: September 16, 2014, 06:49 PM »
Yeah Leo, we can always hope ;)  I agree, this yr. has been not that great.  Noticeably less growth this yr....this air layer is a good example.  Last yr, it would've thrived in the shade.  Like you said, sometimes we win, sometimes we loose ;)

Osoyoung, I'm pretty sure this is what I'll be doing.  Just leaving the mother plant in the box/pumice setup, and bury it and mulch it.  It'll make it.  Not too concerned about the layers, I can try next yr. 
 

sdonny

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Re: cold climate, overwintering air layer questions
« Reply #13 on: September 18, 2014, 06:04 PM »
Thanks for the tips.  I plan to remove the air layers and pot them up, I will keep them outside until fully dormant as suggested.  I'll wait on trimming branches until after the leaves drop and remove branches as required to help keep the pot stabilizing more manageable.  I like the idea of stabilizing in a plastic pot with screws thru the pot into the bottom of the chop that I can then either bury in the ground or put in a wind protected spot such as my greenroom or garage.  The heat mat idea sounds promising too, I might put something along those lines together for next Winter if things don't work out with my current attemps. 

Don't know much about the parent JRM, it is growing in my backyard good size too.  I've had luck with seedlings off this tree as well, although they are growing very slowly in my shaded yard and most of the seedlings seems to have more green in the leaves than the parent tree.  So wanted to get some parent air layers off the branches with some thickness since my little nursery is limited in trees that are ready for potting up and training.  I have only been at it for a handful of years and am currently field growing a variety of local Northeast trees along with my garden JRM for future use.  I have Rhodos, Mountain Ash, White Oak, Beach Plum, American Plum, Crab Apple, Black Walnut, Scotch Pine, White Birch and my Japanese Red Maple.  So, are cultivated japanese red maples typically grafted onto root stock such as with apples or peaches?  I can't see any graft lines on my parent tree.
 

Owen Reich

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Re: cold climate, overwintering air layer questions
« Reply #14 on: September 18, 2014, 10:14 PM »
It really depends on where the Acer palmatum came from.  Seedlings from Acer palmatum 'Bloodgood' and other grafted red leaf Japanese maples are often called Atropurpureum seedlings.  Maples intended for landscape use with red foliage are often grafted.  It varies.