Going through the deep freeze

Discussion in 'Maples' started by maplesandpaws, Dec 6, 2013.

  1. maplesandpaws

    maplesandpaws Active Member

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    I know many of you are now completely buried in cold, ice, and/or snow. Here in south Kansas, we have only experienced extreme cold thus far, with only a small chance of snow forecast for tonight and into tomorrow. So far, it has been overcast and windy, with temps (before windchill) in the mid to upper teens, but it is supposed to clear off later today, still with wind, and our temps are going to drop to low single digits, again before windchill.

    For those in the ground, I have wrapped the trunks of my larger trees with the DeWitt tree wrap, and a few of my smaller trees, or those more exposed to wind, are covered with either a double or triple layer of frost fabric or a large pillow case/double layer of burlap (see attached). For those still in pots, they are all grouped together under the deck and up against the house, with leaves piled in between the pots. The large 5-10 g resin pots are on the concrete patio, but the smaller 2-3g fabric pots are on resin shelves (like from the shelving units, ones with holes in them) with leaves underneath that, so they are not directly touching the concrete. Not shown in the attached picture is the burlap I hung up between the house and the deck on either side of the pots to help shield a bit more wind and *hopefully* keep a little more heat in (I am hoping the residual heat given off by the house will help keeps temps up at least a few degrees).

    Once the cold snap is over, what signs should I look for - or will they even be apparent yet? - to indicate damage? How long can the pots withstand temps like this before the trees start to suffer and potentially die?

    What is everyone else doing to protect their trees during while this nasty system passes through?
     

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  2. Daniel Otis

    Daniel Otis Active Member Maple Society 10 Years

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    I don't know much--anything--about the weather in Kansas, so my experience may not be relevant. I know that I've had big losses among my maples in pots on the few occasions when I've left them above ground over winter. Vertrees said that palmatum has complete root destruction at 14 degrees. That said, I'd be inclined to add more leaves to the trees in pots, if you expect long stretches of temps below 10 degrees. I'd add a couple of feet of leaves if I had them--really cover them up, especially since it doesn't appear that they'll get any insulation from snow under the deck. I've overwintered seedlings in 4" pots many times by covering them with a couple of feet of leaves. But I don't seem to have trouble with mice or voles eating bark; if that's an issue where you live, I don't know what to suggest. Maybe the house and deck will provide enough protection.

    My own trees in pots I either bring into my cold outer basement; I leave the door open all winter when it's above freezing. Previously, I used to bury all my pots so the roots were protected from extreme temps. It worked well, but was an enormous pain. My solution was to give away enough trees that I could fit all that remained in the basement. For my plants in the ground I don't do anything, and they regularly see temps below zero.
     
  3. Gomero

    Gomero Well-Known Member Maple Society 10 Years

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    I agree that 10°F (-12°C) is the threshold for maples in pots, below that threshold they may be killed, I have learned that the hard way :(. Thus if you want to take a low risk approach, put your pots in a place where temperatures remain > 10°F. For Japanese maples in the ground, the threshold is much lower and I encourage you to read the many threads in this forum dealing with growing Japanese maples in zones 4-5

    Gomero
     
  4. emery

    emery Renowned Contributor Maple Society 10 Years

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    I hope you're making it through the freeze. I think the protections look good, but I would probably put another layer of protection like bubble wrap around the pots. I'd wrap it starting in back, so it came under the pots (between pot and cement), then up and over the top. I don't know if this would be necessary, but just as an added precaution.

    It's interesting how, in a worldwide forum such as this, we deal with such differing conditions. Here we've only had a couple of minor ground frosts and many trees (but not maples!) still have lots of leaves. That will change tonight as we have a -3C forecast, really quite cold especially for this time of year. Yet, 3 or so weeks ago we had 10 cm of wet snow!

    I bring all pots inside into an unheated outbuilding for the winter. It will rarely freeze in the room. Some winters this is unnecessary but you never know, we can get a couple of weeks around -12C or even a bit colder. In 2008/2009 we had the coldest winter in most memories, it dropped to -23C! We lost many Chinese maples that were in the ground, and a few Japanese maples also, often when the understock was less hardy than the graft. I used to bring most of the pots outside while the weather was warmer, but schlepping them back in and out was pretty Sysiphean...

    Still our problem is mostly the wet, not the cold. I think the trunk wraps will work very well for you, whereas here I fear they would trap in moisture and cause real problems during the cycles of freeze and thaw that we see much of the winter. Another indication that there is no one-size-fits-all solution, we all have to "pay the dues" to Mother Nature locally! :)

    -E
     
  5. maplesandpaws

    maplesandpaws Active Member

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    We woke up to a balmy 4F Saturday morning, -12F with windchill. UGH! (Though, I must conceded that while it was cold here, I am very happy I was not back home - Alberta, Canada - where they were sitting at a lovely -40C with windchill. For those who don't know, -40F and -40C pretty much coincide - d**n chilly, no matter how you slice it.) The night before, I went out and did as Daniel suggested, and added a bunch more leaves over and around the pots, as well as put 4 large yard trash bags full of pine needles around the perimeter of the trees. Thankfully we had sun most of Saturday, even though it didn't warm up above 20F, and where the pots are under the deck, they do receive a good dose of late morning to early afternoon sun, hopefully enough to help warm them up a bit. Since then, we have been warmer (relative term), with the nights hovering around 12-15F, and daytime temps in the low to mid 20s. After today, we are supposed to finally start warming up to above freezing during the day, with a bit more sun in the forecast (cloudy yesterday and today).

    Some of you mention about putting potted trees in garages, unheated basements, etc... The last two winters, with the exception of a few of the large ones, I kept all my potted trees in the attached garage - unheated, but insulated. Come spring, I easily lost half of all my maples. They would start out fine, leafing out nicely, then the dreaded black spots would start appearing on the trunk, or where smaller branches came off larger ones, or off the trunk, and it would just spread from there, resulting in inevitable loss within a month, give or take. This is something that I did not want to go through again, it's too heartbreaking (never mind the toll on the wallet). After talking with a master gardener at our local extension office, as well as a horticultural expert at one of the local universities (where the extension office sends plants, soil, etc, that are brought in by the public for testing), we all came to the conclusion that keeping the pots in the garage was the likely cause of the losses - the plants weren't able to go fully dormant like they would outside, the (likely) higher humidity in the garage, and the larger temperature swings in the spring of being brought in and out of the garage for cold/warm days. So this year, I decided to keep all my pots outside in the hopes that I would not, yet again, lose half of my collection. Plus, as you so eloquently put it Emery, "schlepping them back in and out was pretty Sysiphean..." - couldn't agree more (though, I think my husband might be able to! lol).
     
  6. Daniel Otis

    Daniel Otis Active Member Maple Society 10 Years

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    Sorry to hear about your losses over past winters--I would find that extremely frustrating. I must say, the losses surprise me--I've been growing potted trees in my cold basement for 20 years. I'm in the same zone as you, 6a, 6b. I leave the trees outside until the end of November--ideally, I'd bring them in as they lose their leaves, but some always hang onto their leaves until December. But all are fully dormant when I bring them in, and by leaving the door open I try to keep them at outdoor temperatures except when it's going into the lowers 20s, throughout winter.

    I've lost a few from letting them dry out excessively over winter, when it's easy to forget watering. My main problem, though, has been that, given the relative warmth of the basement, they break dormancy too early and produce etiolated growth in the dark long before they can go outside for good (generally on about the 20th of April). It finally occurred to me that I should take them outside BEFORE they break dormancy. This slows the pace of premature new growth considerably, and on nights when it's excessively cold I spray them with water and cover them with a gigantic plastic sheet. Much easier than moving them in and out with the weather, which I did for years.

    You may have greater, or more sudden, fluctuations in temperature than we do here, or perhaps earlier, warmer temps for days at a time. I do wonder if your extension person is right about the humidity issue. For me, at least, it doesn't seem to be a problem. In my cold basement, I now water the dormant plants with a hose every month or so, so it's usually very humid, and if we have a rain when there's deep snow, there may even be an inch or two of standing water for a few days (the plants are off the floor). It doesn't seem to bother them. Because the basement is underground, it doesn't experience dramatic temperature shifts.


    The fact that they break dormancy but then collapse suggests to me that the problem is at the roots--perhaps excessive cold after root growth has begun, but before the leaves have begun to emerge?

    Well, best of luck with your approach this year. Let us know how things turn out.

    D.
     
  7. JT1

    JT1 Contributor 10 Years

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    I had a similar experience with a 3 gallon maple. I had tried a new soil mixture two seasons ago, mainly because I was out of a couple components and wanted to get the tree potted with what I had, which resulted in the mix being heavy in sedge peat. The tree leafed out fine and seemed to be happy early Spring. A couple of weeks later it started to struggle. Once the heat and humidity increased, the black spots started showing up on the trunk and the leaves were failing. The sedge peat retained too much water and really limited the roots ability to breathe. I quickly realized the problem and took it out of the pot and I could tell the roots were un-healthy due to the swampy soil. I mixed up some soil with less peat and increased haydite for drainage and aeration. The tree recovered in the shade. (note, I do not fertilize a tree with black spots) By mid-summer it leafed out again and did pretty well, all things considered. Last season it did quite well. The black spots still remain, but they have not gotten any bigger, so as long as I keep the tree healthy the black spots should stay the same size.

    I would recommend adding some haydite to your soil mix to help combat root related problems, if you continue to have newly forming or growing black spots in the bark. Soil mixes containing peat are good in my opinion, but too much peat in the mix can result in root problems in humid conditions. Too little peat results in a mix that dries out too quickly. I have noticed its all about balance in my experience and observations of growing maples in containers.
     
  8. maplesandpaws

    maplesandpaws Active Member

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    I'm glad to hear I'm not the only one who has experienced this, though mine was on a much greater scale (about 10 plants each spring for the past two years). While of course I can't be 100% certain on anything, I don't *think* my soil mix is the culprit, as it is quite free-draining - equal amounts of Ocean Forest potting mix (contains perlite), pine bark mulch, turface (which is very similar to haydite, as I'm sure you're aware) and coco coir, torn up into 1/2"-1" chunks. This mix has good moisture-retention, yet is loose and (in my experience) doesn't allow the soil to become swampy. As I recall, I only watered the pots in the garage once a month?? Something like that anyway... Either way, I'm hoping that the extreme cold thus far this season doesn't cause me to lose any trees due to freezing... :(
     
  9. JT1

    JT1 Contributor 10 Years

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    When I said swampy, it was a bit of an exaggeration. The high peat soil blend was holding too much moisture for some Japanese maples to handle. The tree with the problem was a grafted mikazuki. A mikawa yatsubusa and sensu did not seem to mind it. Actually now that I think about it, an akita yatsubusa was not happy with it either and started to develop a few spots, but it was much further behind the mikazuki in decline. They were all 3 gallons from Buchholz Nursery. I have found that some varieties are more sensitive to overly moist soil than others.

    With the black spots that lead to sudden decline, I believe that infected understock within the industry is a big part of the problem. The infection is transferred to the scion wood and all it takes is a combination of stress and a weak variety or weak tree in general to bring the infection out. If the tree remains strong and unstressed, then you will never know its there.

    Back to cold weather...
    You should check out a story in BCI magazine 2012, 4th quarter, page 37. Its written by Enrique Castano de la Serna and focuses on Abiotic factors in container grown trees/plants. Its a great article and the author goes into detail on hardiness and factors that will impact hardiness and the health of an overwintering tree. Its written to give you an understanding of these factors with the idea that no two climates are the same. So if you understand what impacts hardiness, then you can apply that understanding to your climate and combat those challenges specific to your area.
     
  10. JT1

    JT1 Contributor 10 Years

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    When you have large losses, its usually a large scale / universal problem and that's why my initial thought was something universal like soil and moisture. Those that lived, had a higher tolerance to the problem than the trees that did not make it. If its not soil, then I have one last theory for you to consider....

    (Sorry for the long response, but try to stay with me despite my inability to shortly sum it up...Lots of good points to make, it just takes me a while to explain)

    I think we can both agree that Summers in your area can be very hard and challenging to say the least. So a dormant period, or rest and recovery, is very critical to the long term survival of your trees. My guess is they go into Fall pretty exhausted.

    So its critical that you do everything you can to reduce winter stress and sharp temperature swings to give your trees the best quality rest possible.

    Very Important to Consider.....For maples to rest, they need to go below 45 degrees F. For quality rest, its important that the root zone temperature does not fluctuate above 45F on a regular basis. They need 100-1300 hours of rest or time below 45F. For best quality, they should have limited interuptions (or temperature swings). Keep in mind that in the ground, soil temperature in the root zone is very slow to change. It is much more stable than the root zone temperature of a above ground pot. The smaller the pot, the greater ambient temperature influences root zone temperature. That is why small pots should always have additional protection from not only the cold, but the warm ups too. ("cold" meaning sub-freezing, although maple roots tolerate sub-freezing temperatures, it becomes a stress that can lead to root damage as the root temperature gets colder than sub-freezing. The damage usually occurs as the outer roots hit the critical temperature, as inner warmth is loss, the damage works inward. Where as, the term "warm ups" would be that time spent above 45F, breaking true rest)

    With that in mind, here is my theory....
    I think your maples went into winter dormancy stressed from Summer (it is what it is, not your fault, its just how it is in your area's extreme summers). You lovingly put your maples away in your garage for winter (its what most people do). But how often did your garage go below 45F and stay there long enough for the root zone temperature to fall below 45F? Keep in mind the root zone temperature is slow to follow the ambient temperature.

    To make matters worse, if you were taking your trees out of the garage into the daylight / sun periodically, this would warm up the root zone (its amazing how winter sun can warm up a pot even though its very cold outside). Then at night, the root zone temperature is slower to fall than the ambient temperature, so some or many nights it may not have seen 45f at all. This interrupted rest and swings in root zone temperature adds a great deal of stress to some already stressed trees. Not to mention, this time outside may have lead to moisture loss and the one month watering may not have been enough. Just for conversation sake, lets say it was enough moisture for survival and that was not the cause for decline.

    So now Spring comes and your trees had very little time to rest (or little quality rest time below 45F). They also had some additional stress from swings in temperature too (that time out in the sun over winter is not helping, its hurting). They leaf out in exhaustion and collapse.

    Why did some make it while others died, if its a universal problem? The stronger varieties or less stressed trees going into winter manage to survive and live another day. (consider that maybe they are less stressed because they made it through last summer better, entering dormancy with more energy reserves and overall strength, because they were not as depleted. Maybe the survivors were in a more sheltered position during last summer or they were a variety that can handle summer extremes better with less stress. Maybe they were late season purchases from another area that went into winter less stressed). But can these survivors make it long term? If they get through the Summer and have another un-restful winter next year, then chances are that they are on borrowed time.


    Side note, tip / FYI...An inexpensive digital weather station with a additional remote sensor in your garage or cold storage is an easy way to monitor temperature (and other factors like humidity) from the comfort of your home. That way you are not running on guesses and assumptions, you know the exact temperature. Some of the fancier ones identify trends and even store days worth of temperature high/low history. Now you are not guessing on temperature and it can be monitored accurately, conveniently, and efficiently. Of course a good old fashioned thermometer will tell the temperature, its just harder to monitor it or identify trends within your cold storage, without constantly going out there to check.
     
    Last edited: Dec 14, 2013
  11. maplesandpaws

    maplesandpaws Active Member

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    As always, you bring up some very good points, and some things I had not considered...
    Not saying it couldn't be the soil, and your arguments below do support that possibility, but I don't *think* so. I am definitely willing to try different components/ratios/etc.

    And how. This past summer wasn't too bad, but the previous two were awful on the maples, and most of my plants in general - over 50 days of daytime highs above 100F, nights not getting below 90, and very, very little rain.

    The garage is unheated, though it is insulated. There is one small window on the south wall, but it has a closed venetian blind over it. I know it got below 45, but for how many days/hours, I do not know. Obviously on the warmer days, it would warm up as well.

    I would only start moving the trees in/out of the garage come spring, when it would start to warm up; never during the dead of winter. But, the trees in the garage definitely started pushing new growth earlier than those outside. I do recall seeing buds forming/starting to swell several weeks prior to the few trees that were left outside.

    Definitely makes sense, and appears to be what has happened with the trees that I lost.

    As far as my losses this past spring, I do know that many (all??) of the trees I lost had significantly swelling buds, almost to the point of opening - the second growth spurt - in mid- to late October, just shortly before we started turning colder. I think this very late surge occurred for a couple of reasons: First, summer was so very hot, for so very long, the trees went into self-preservation/semi-dormant mode, not daring to push the second flush, because conditions simply were not suitable to do so. When it finally started cooling down to reasonable temperatures - mid- to upper-80s for daytime highs - it was already halfway through September. When the trees finally started waking up and going into active growth mode, they were doing so on borrowed time. Second, and this is my mistake, one that I won't be repeating (and didn't this year), I gave all the trees a small dose of mild fertilizer in mid-September, once the temperatures were suitable to do so. This, combined with the (finally) lower temps conducive to pushing new growth, probably set the trees into overdrive. So, because they were already stressed from the long hot summer, stressed from pushing a second set of growth so late in the season, which was suddenly cut short with winter's arrival... All this was simply a bad, bad combination. I can't speak to the previous fall/winter/spring, but I have a feeling this was likely the case as well.

    I think this is something I'm going to have to pick up, and of course I can always move it from the garage in winter to elsewhere in summer if I need to keep track of things.
     
  12. maf

    maf Generous Contributor Maple Society 10 Years

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    The cycle of initially leafing out in the spring and then running out of steam does suggest a root death issue, as mentioned by previous posters. But, then again, the weird and stressful for jm's weather/climate conditions in your area throw a spanner into the works as well, especially when new growth occurs in the late fall. Your soil mix sounds free draining enough, but without seeing it in person it is not possible to rule it out entirely.

    If the situation recurs (I hope it doesn't) a thorough post mortem examination of the root zone, including checks on soil structure, soil moisture levels, as well as observing the level of health vs decay in the roots themselves, will tell you once and for all whether the problem originates in the soil. It would also be good to get some temperature data from the storage area so the weather station idea is definitely worth following up on too. Make sure you get one that records the max and min temps in any given period (probably a standard feature). I hope you have a better winter this year.
     
  13. JT1

    JT1 Contributor 10 Years

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    Back to soil, I have one more point to make...
    Our soil mix can have all the components of a great soil mix and still pose problems if the ratios are not correct.

    Tip: A great way to make sure our soil component ratios are correct, do the crumble test...

    Mix up the soil and grab some in your hand and squeeze it together in your palm, then release. If it retains its shape, then add more haydite or aggregate. Mix again and try the crumble test again. Once the soil no longer retains the shape and crumbles apart, then you are good to go. (If it retains its shape then I have found in general that leads to compaction and means it will retain too much moisture and limit oxygen to the roots = root problems; if it crumbles, this tells me that the soil will resist compaction and allow more oxygen into the roots = healthy roots and happy maples. My wife gets so frustrated with the crumble test. She knows what components to mix into the soil but is still learning the ratios. She always wants to get it done NOW, where I like to take my time and make sure its right. After making her re-pot a couple of newly repoted trees, she has learned the value in the crumble test and that it takes less time than having to do it all over again. I rarely get it right on the first try and always find myself needing to add more haydite after the first crumble test. I prefer to sneak up on the right ratio than to have too much aggregate and it crumble too easily, which usually means the soil will have too much oxygen and dry out too quickly)

    Back to cold hardiness...
    Fun fact to always consider: Did you know hardiness changes through out the winter?
    Most people do not really stop to think about that fact. We tend to take the zone hardiness that the books or grower's website states for face value and we feel secure. This is a false sense of security, because there are several factors that impact hardiness that we should always consider when contemplating winter protection.

    First thing to consider in early winter is hardening off of new growth. If the temperature drops below the hardening capabilities of the new growth, then we run into real problems with damage, which could lead to decline, disease, and even death in an already weak tree. As hardening stays ahead of temperature drop, our trees can tolerate colder temperatures that usually occur in mid to late winter.

    Tip: We should all start making winter preparations related to growth and hardening off during mid-summer, especially those of use that experience early winter extremes. I start by using 0-10-10. When a guy like Jim (Mr. Shep, who is a legend in my mind) says he uses it to allow trees to grow at higher elevations, beyond their stated hardiness, then you know it works. I happened to stumble upon using it and thought it worked, but when Jim mentioned he uses it, then I knew for certain that it works in hardening off new growth and increasing winter hardiness. Another thing is to not promote late season new growth by over watering and or using nitrogen fertilizer too late in the season. Because my winters can start so abruptly, I play it safe and do not use any nitrogen after June and I rarely use it in general as my belief that more harm than good comes from using nitrogen fertilizer on Japanese maples (especially in my climate).


    Other factors that impact hardiness are:

    -pot size (small=less hardy because they are less resistant to cold invasion that can quickly cool the roots down to that critical temperature that root damage occurs. Always give small pots extra protection; larger pots have more of a core of protection from the whole root zone reaching that critical temperature that root damage occurs. A larger pot will stand a longer period of ambient temperatures at or below the critical temperature before root failure occurs. Where a small pot may suffer root damage all the way through, killing the tree; a large pot may only suffer damage on the outer roots and live to see another day)

    -wind and sun exposure over winter (exposure to high wind can reduce moisture and temperature. Exposure to afternoon sun can increase stress and damage due to rapid cooling after sunset, which can also result in bark damage too)

    -Mulch and snow cover (mulch and even snow cover helps insulate roots from cold invasion and moisture loss)

    -Establishment (Is the tree established or new to your environment? If not, then it will be less winter hardy and require more protection, where an established tree that is acclimated to your environment will be more winter hardy)

    -Moisture- offers more resistant to root zone cooling. I try to time my winter watering's before a big drop in temperature. Of course, you can't water before every drop, because it would result in root damage due to being too moist. So with that said, the key is don't let your pots go into a deep freeze dry and then water after the fact, rather try to water (if needed) before the deep freeze to offer more protection from extreme cold invasion into the root zone.

    -Growing season stress- A tree that is stressed over the growing season is weaker and has less energy reserves. A stressed tree will always need additional winter protection, because they are less winter hardy.

    Genetics- After everything above is taken into consideration, we can consider genetics play a role too. One example of this is that I have found Acer shirasawanum to be more hardy than Acer palmatum. Within Acer palmatum (US category of palmatum), I have found some varieties to be harder than others. For example, my trompenburg is bullet proof during summer heat and it takes a winter wind beating and never has die back. Where my Shaina has all kinds of protection and still has some die back. As a general rule witches brooms and mutations are not as winter hardy and need more protection.
     
    Last edited: Dec 15, 2013
  14. maf

    maf Generous Contributor Maple Society 10 Years

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    JT, Trompenburg is a palmatum/shirasawanum cross, so extra cold hardiness is likely to be present there. I have heard several reports of cold tolerance for this maple cultivar.

    MP, I particularly wanted to comment on this point:
    In the UK there is a supplier af Acers that grows everything in a greenhouse in Holland with the result that their plants are not best adapted to winter conditions, and I have lost some and had dieback in others following the first winter. If you have bad winters it is likely best to buy maples from a grower in your own climate zone rather than a milder zone.
     
  15. JT1

    JT1 Contributor 10 Years

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    Thanks for sharing...I often would notice that the seeds would stand proud of the leaves in Spring and it made me wonder if it was related to shirasawanum. Now that you mention it, the winter bark on the trunk and the thick new growth at the branch tips are a strong indicator of shirasawanum too.

    Tamukeyama, Atrolineare, and Amber Ghost are a few others that do very well in harsh winter conditions in my area.
     
  16. maplesandpaws

    maplesandpaws Active Member

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    I really, really, really hope it doesn't recur again this spring, I don't know if I could take the heartbreak (not to mention $$ loss) again - and of course, I would pick what appears to be one of the colder winters to try over-wintering the pots outside. :( Should it happen though, would you suggest having the soil/roots/trunk/branches tested for pathogens? I will have to see if I can pick up a remote temp gauge shortly; would you suggest placing the remote sensor on one of the smaller pots (but under the leaves) to get the most accurate reading of what the root zone is experiencing? Where I have the pots, I am not really concerned about wind damage; between being under the deck, up against the house, and then the double-layer of burlap I strung up between the house and deck-stairs, they will get air movement and breeze, but no true wind. It's the extended cold temps that worry me.

    I have not done the crumble test on my soil (though I have heard/read about it before), but I certainly will do so this spring. That being said, with all the larger/chunky pieces in my soil mix (the bark mulch - which I don't sift, though I do remove the really large pieces - and the coco coir are usually 1/2"-1" or more in size, plus the turface which is about 1/4" or so), I don't believe it will 'fail'. I too have struggled with getting just the right consistency for our climate - water-retentive enough that I'm not watering every few hours in the dead of summer when it's 110F with 35mph winds, yet not so water-retentive that the roots end up sitting in a sauna. Then conversely, we have the cold, typically drier winters... So many extremes.

    This is likely a large factor in what happened last fall/this past spring - the late season push of new buds/leaves, and the sudden drop in temps before this growth hardened off.

    The fertilizer that I have used the past 2 years is the Fox Farm Japanese Maple organic fertilizer, 4-8-5. It's kind of powdery/granular in texture, and while it's not a time-release fertilizer, it doesn't break down right away either. (I've actually been using this on nearly all my potted shrubs, etc, and they all seem to be doing well with it. My flowering plants I use a different fertilizer.) As mentioned in my earlier post, this year I did not fertilize after early summer; because this summer was milder, overall, than the previous years, I cannot say for certain whether or not the lack of a late fall growth spurt was due solely to this or not, but I do hope it helps with my spring issues.


    I did water - not a thorough soaking, but not a quick sweep either - all my in-ground and potted trees the day before the cold snap hit, so I am *hoping* that this gave extra insurance to those trees in pots, especially the smaller 1-3g pots.
     
  17. rufretic

    rufretic Active Member

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    I'm not as experienced as some of the others helping but my method has been 100% successful for the past two winters so I'll share. What I do to protect the maples I have potted through our cold winter is pretty simple. Once they loose their leaves and the temps start dropping below freezing on a regular basis, I move them into my unheated and uninsulated attached garage. I take each pot and put them in a larger pot just large enough to make about a 2-3" gap all the way around including the bottom. I fill the gap with peat moss to help insulate the roots and also throw about an inch or two on top. Then I put them all about an inch off the concrete floor by just using what ever scrap wood I have in the garage. I don't water all winter long but every time it snows I put about an inch of snow on them, as it melts it waters them like it would if they were in the ground outside. I do keep a thermometer out there to keep an eye on the temp. I never let it get below zero but I only had to turn on a little space heater twice last year.
    This has worked well for me. I've done it with about 50 maples, 4" starter pot up to 7 gallon containers. Have not lost one yet but they get planted as soon as the ground thaws in the spring. I don't keep any maples potted, I just use this for anything I didn't have time to plant in the fall or purchased during the winter.
     
  18. emery

    emery Renowned Contributor Maple Society 10 Years

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    I couldn't agree more on the importance of the "crumble test", but I found that even that is not a guarantee that substrate is performing correctly. A few years ago I was using a component labeled as "citrus soil," which was fine and sandy, free draining but held moisture well. I figured adding a little (maybe 1/10) of this would help retain moisture; but what ended up happening was that because of the much smaller particle size, it washed through the other components and basically collected at the bottom of the pot. There it stayed a muddy mess, and while it didn't kill the plants they hardly thrived; the bottom of the root zone was a mess, wet and black. For JMs I don't use any soil addition now, although one of the coir products has some rotted seaweed in it.

    Another measure I hadn't thought to mention before, sorry my head isn't quite screwed on just now! ;/ I spray the winter plants, both inside and out, with copper sulfate 3 times during the winter: once at the beginning of winter (just as the pots are going inside, these get sprayed with fungicide also as there is quite high humidity in the outbuilding, unfortunately) once in January, and again just as the buds start swelling. I've found this practice has really helped with pseudomonas and related dieback/black spot.

    @maf, I usually keep maples from the greenhouse you mention in pots for 2 years before planting, or at the least one season... in fact I got a rooted Dipteronia (Acer dielsii anyone?!) which I stuck directly into the ground, your comment makes me wonder if that was an error... Anyway buying local or from a similar climate where possible is really terrific advice.

    -E
     
  19. JT1

    JT1 Contributor 10 Years

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    Rufretic - Great tip(s). I will add a few points for others (out there in cyberspace) to consider, but I am in no way trying to convince you to change what works very well for you. You and I are very alike when it comes to garage storage concepts and practices.

    I use sphagnum peat around my small pots and bonsai too. I like sphagnum peat because it stays dry and fills very nicely. [Then I recycle it come Spring by top dressing the outside beds with the peat and mulch mix (nothing is wasted, win/win).] One shrink wrapped bail usually does the trick for me. Sometimes the home centers clearance them out as fall arrives, so it's a very cost effective means of winter protection. It helps get the little ones through winter, then benefits the landscape once spring arrives.

    I think the only difference is that I use mulch to set my pots on, before adding the peat for winter preparation / protection. Then I add mulch to the surface for additional protection and prevent moisture loss (not peat). I happen to water instead of using snow.

    Recycling tip- save your larger nursery pots to use for this purpose of overwinter protection. For example, a small 3 gallon maple can go into an empty 5 gallon nursery pot. Add mulch to the bottom of the empty 5g pot, to raise up the tree in the 3g pot, which adds an area for extra water to drain. Add sphagnum peat between the pot walls for insulation and add some mulch on the surface. Pot in pot protection works very well with peat used as a root zone insulator / protector in between the pot walls.

    For shallow pots, bonsai, or rectangular pots. Get a plastic storage bin (or bins) for a table top storage place or storage on the floor. Add mulch to the bottom to level your small pots, then fill in around the pot walls with sphagnum peat. Mulch the surface for added protection.

    This not only protects the pots and trees from extreme cold, but it also protects them from getting too warm and leafing out too early.

    Also, raising pots off the ground with scrap wood or bamboo rods work good too (don't block any bottom drain holes though). This is a great tip too. Concrete will condense with warm ups and seal the bottom of a ceramic pot to the floor in an unheated garage or shed. This is like having your pot sitting in water and blocking the drain holes. As we all know maples hate this and it can cause root problems and disease, so raising your pot up is also a great tip worth noting too, when considering winter protection / storage methods.

    Lastly, if you are in the market for a new garage roof (that is unheated and detached from your house) and use your garage for winter storage, have them put in a ridge vent. My garage humidity problems became a thing of the past, when we had a ridge vent installed with the new roof for our garage five years ago.
     
    Last edited: Dec 17, 2013
  20. JT1

    JT1 Contributor 10 Years

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    The only way to know the root zone temperature is by using a temperature probe of some sort to take a core reading inside the pot. I would not even know what product to recommend, since I never needed to be that exact in measuring.

    I would put the sensor in a shaded area of your storage area close to where your maples are for best results (but not right on the house or on the ground as this may give false readings. Knowing very little about the storage area from posted pics, I would tend to put it on a shaded deck support post in close proximity to your pots). I think you will find that this area will stay warmer than the "advertised overnight low" on the TV weather. The foundation area of your house retains warmth and that is why the snow is usually quicker to melt there or tends to be shallower 24 hours after a heavy snow fall. Foundation beds are usually the first to melt. [In fact the guy across the street planted tropical flowering vines against his foundation and to our surprise, they come back every year.] The deck above will help somewhat with heat loss too. It should also help protect from frost too.

    Once Spring arrives, move the sensor to the patio. That way you know the official patio temperature, which is most important during the growing season for maximum enjoyment!
     
  21. rufretic

    rufretic Active Member

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    Nice detailed follow up JT. You hit some details I didn't mention, like not blocking the drainage holes. Using mulch at the bottom instead of the peat is also great advise. I did that last year until I ran out of mulch and then just used all peat moss with the rest. It didn't seem to make a difference for me but I don't water, just a small amount of snow to keep them from drying out. For someone who is going to water, I agree mulch at the bottom is a much better option to make sure they aren't sitting on top of soggy peat. I also just reuse the plastic containers I've kept around from previous purchases. I use the peat moss in the spring as well. It's a cost free way of winterizing if you plan to buy peat moss in the spring anyway. The roof ridge vent is also a good mention. My roof is vented all the way around so I'm sure that is why I've not run into any humidity issues.
    It's good to know this method works for you as well, gives me extra confidence that my new maples will make it through winter again.
     
  22. copperbeech

    copperbeech Active Member 10 Years

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    We are having an almost unprecedented "deep freeze' for our area. For the past week or so low temps (without windchill) have ranged from -18 C to an almost record setting -24 C (0 F to -11 F). I have no maples in pots but such prolonged cold could no doubt impact on in ground maples :(. If for example my very puny "Olsens Frosted Strawberry" survives its first winter in the ground I will be more than pleasantly surprised. But it would be the loss of my second year Acer shirasawanum Aureum and first winter but large Filigree Green Lace would be most disappointing.....fingers crossed.
     
    Last edited: Jan 4, 2014
  23. maplesandpaws

    maplesandpaws Active Member

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    Copperbeech - for the GTA, that is very cold for you; I hope your trees make it!

    We too are going to get very cold again these next few days - Sunday night we are supposed to hit 0F, or -4F, depending on which weather service you go by, before windchill. Obviously, yet again, my biggest concern is my potted maples and conifers. I plan to water them today (last watering was 2.5 weeks ago) since we will still be above freezing this afternoon; should I also water the in-ground trees? We had roughly 1" of drier snow the beginning of this week that took a day or so to melt off, and the previous week, we had 4" that finally finished melting just before we got the lighter snowfall (the 4" wasn't dry snow, but it wasn't heavy, wet snow either).

    Like copperbeech, with such cold temps, should I also be worried about the in-ground trees? The few larger ones have the DeWitt Tree Wrap around the trunk and up the largest branches; I do have 3' wide burlap that I could also wrap around them - yes/no? For the potted trees under the deck, I had already added extra leaves around, in between and on top of the pots as best I could, but with this significant cold snap, I am also thinking trying to prop up some large t-posts/tree stakes in between the pots as supports and then placing some large old sheets 2-3 layers thick over top of everything; would this provide that little bit of extra protection for them, or would it not be worth it? Unfortunately, it is supposed to start clouding over later today through Tuesday (the coldest days, of course), so the under-deck trees won't have the benefit of the sun shining through/under the deck to help warm them during the day.

    Suggestions and recommendations for this latest round would be greatly appreciated! :)

    Side note - I think this has been an excellent thread regarding cold-weather protection, and the numerous factors that go into the health of a tree in prepping it for such stresses. Thanks everyone for all your comments and feedback!!
     
  24. rufretic

    rufretic Active Member

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    I'm also about to get hit by some nasty temps. They are saying -20 and possibly -50 with windchill! If they are right it will be the coldest we have got since I have been collecting maples. Thank god we got about a foot of snow on the ground to help insulate the roots but I'm not sure it will be enough. This will be a true test to which maples are hardy enough to survive in my area. I have over 100 in ground so I'm praying most survive but if I loose a lot of them I will be devistated and might have to look into something new to collect. :-(
     
  25. maplesandpaws

    maplesandpaws Active Member

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    Was really nice up until about 1:30, when the winds switched around and started coming in from the north - went from sunny and 40 to cloudy, very windy and 25 by 3:30. Brrrrrr!!!!

    Got the plants covered, with the t-posts acting as braces for the sheets. The sheet nailed to the joist for the deck (north end) should block the vast majority of the wind, and *hopefully* the one post standing straight up won't fall over (crossing fingers). Watered the pots before covering them up at 4pm; hopefully they will make it through the next few cold days.
     

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