Damage from overwatering, wind, verticillium - or all three?

Discussion in 'Maples' started by Rosy_S_Cenario, Oct 25, 2016.

  1. Rosy_S_Cenario

    Rosy_S_Cenario New Member

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    Dear Japanese maple lovers,

    I don't know what I'm doing wrong! In early April this year, I bought two ten years old JMs - an Acer Mikawa Yatsubusa and an Acer Autumn Moon. They're both giving me some grief and, after perusing many forums over here (Europe, USDA zone 7 or 8 depending on whom you ask), I have not found out what I am doing wrong, if I did not read the trees' signs right or if I'm just plain stupid - please have a peek at the two photos attached.

    The details:

    - Purchased in containers 2nd week of April
    - Pots Ø 45cm with fairly organic soil and some grit so as to provide drainage
    - Added a little low nitrogen fertiliser in the soil mix

    - Wooden terrace 2nd floor facing south-west
    - Direct sun exposure from 09:00 - 11:00 and 15:00 - 17:00
    - No exposure to rain

    - This year May, July and August 1-2 weeks with up to 37°C (23° at midnight) and stormy winds more suited to the Philipines, very unusual over here
    - Watered daily at the exact same time 1l, on those scorching days twice per day
    - Moved both plants as close to the terraces' windows/walls to reduce wind exposure

    - 9th July both plants showed brown leaf tips
    - 20th September both had very many fairly brown leaves, mostly away from the house; particularly the Mikawa had lost fairly many leaves on two branches
    - 23rd October the Mikawa has buds emerging on several twigs on those branches that dropped most leaves

    So, did I "love them to death" by overwatering them when in July I detected a brown leaf tips, not knowing it could have been damage from the hot winds, sometimes blowing hard all night, too? Did the soil I bought contain the verticillium fungus?

    The climate here should(?) to be good for JMs, from what I can see on other inner city terraces, balconies or rooftops; but maybe this year's insane weather was responsible - and then I added my fair share of rookie mistakes?

    Also, how often should I water potted JMs from November - February? There is no garden shed or garage where I could put them during the dormant period : (

    Any help or suggestion would be so much appreciated!
     

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  2. maplesmagpie

    maplesmagpie Active Member

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    The lower photo is how they look now? Honestly, that's not too bad considering this is their first year in a new environment, they're post-transplant, and you had some extreme weather. The one thing I wouldn't have done is fertilize them. I doubt you purchased soil with verticillium.

    I haven't been doing this for that many years, but I definitely see a pattern of trees looking ugly the first year after they arrive. It's not a rule, but it's true the majority of the time. Trees take some time to get used to their placements. I think next year you'll see better success with your foliage. Just make sure you give them the right kind of potting mix and don't let them dry out or get swampy.

    If you see twig blackening, then clip out that part of the plant (going below it by a few inches at least if you're really worried), then sterilize your tools well. You can spray the area with a copper-based antifungal spray if you want. Protect them from sub-zero temps this winter, and especially from wind. Next spring make sure they get at least a couple of copper spray treatments before the leaves come out. Good luck! Hopefully someone with more experience than me will chime in, too.
     
  3. Rosy_S_Cenario

    Rosy_S_Cenario New Member

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    Thanks!

    Yes, the lower photo is the latest one I took (date in the lower right corner). I did all pruning with clean clippers and will wrap the pots, lifted on styrofoam discs off the ground. Maybe I just need to see how the 2nd and 3rd year goes in the new environment after 10 years in the nursery.
     
  4. maplesandpaws

    maplesandpaws Active Member

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    Rosy, I concure with Maplesmagpie - for the first year (especially in a completely different environment than the past 10 at the nursery), they look pretty good! Since maples have thinner/softer leaves, it's almost impossible to avoid some burning/browning at the tips if you have excessive wind for more than a day or two in a row. I think thus far, you're doing everything right. :)

    Going to the upcoming issue of winter, though, since you're on the second floor, and the trees are on a balcony, protecting them once the cold temperatures hit will be critical. Unfortunately, being elevated like that means that temperatures will be slightly colder than what they would be at ground level. Also, they won't have the insulating factor of the ground to keep the base of the pot slightly warmer (I'm guessing your balcony is metal??). Putting a good layer of styrofoam underneath the pot will help with insulating the bottom - but be careful you don't impede drainage!! Especially in winter, constantly waterlogged soil/wet roots can kill a maple faster than just about anything else. For wrapping the pots - another very good idea - try to wrap some of the styrofoam insulation, or a few layers of bubble wrap, around the pots first, then wrap several times with burlap, a heavy blanket or the like. You want to trap the heat against the pot as best you can, and then put them as close to the wall as possible, to take advantage of some of the radiant heat from the building. Another option is to 'wall off' the area of the balcony where the trees will be with some sheets or burlap, creating a sort of cold frame. This again will help trap some heat closer to the trees (sometimes even a degree or two can make all the difference), and will help block the worst of the wind (another killer for maples in winter). Using sheets or burlap still allows air movement and helps prevent the buildup of excess moisture in the enclosed area; using plastic creates stagnant air, a perfect breeding ground for fungus and bacteria, and also has a risk of getting too warm when the sun shines on the area. On warmer and/or sunny days, simply pull the sheets back to prevent the area from getting too warm. This is what I do in winter for my trees; I wall off under our deck with old sheets but keep them pulled back. Once the really cold temperatures hit, I close everything up, using clamps to hold the sheets in place/closed.
     

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  5. Rosy_S_Cenario

    Rosy_S_Cenario New Member

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    Thank you so much!

    I feel more encouraged now. You can see in the photographs above that the terrace is made of elevated wooden slats with about an inch of space underneath. I actually ordered styrofoam disks and burlap to raise the pots and also wrap them. Then, I'll put them all next to each other as much as possible, because curtaining off part of the terrace is not allowed in our multi-storey property. I meanwhile read also, that, to prevent bark-split, wrapping the lower part of the trunk with a bit of burlap could be a good idea.

    What would you recommend regarding watering potted trees during the dormant period? Once a week on days without sub-zero temperatures? Or even more rarely?
     
  6. Keke

    Keke Active Member 10 Years

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    I don't know, you guys. I'm in a Vancouver townhouse, and we have a couple of Japanese maples in pots on our roof deck (full sun all day, windy because we are on the top of a hill, but not as hot in the summer). We have one more potted on our front patio, which is more sheltered and doesn't get as much sun. We have never in our three years here gone to those lengths in the winter for our potted maples. Admittedly it normally doesn't snow much here, but we do get temps down to -8C in the winter for periods of up to a week. Before we lived at this address, we lived in a suburb and had many more maples -- my husband adores them. It snowed a lot more there, and temps went down to -15C maybe once every couple of years but -10 most years. Again, no specific additional care. Yes, in the first year they all looked ratty. Better the second year, and just fine in the third.

    The one thing I would make very sure of is whether the pots are large enough. A good volume of soil will insulate the roots quite a bit as long as the root ball is not waterlogged. 45 cm pots should be just fine.
    Hope this helps. Those trees are hardier than you think!
    Keke
     
  7. Rosy_S_Cenario

    Rosy_S_Cenario New Member

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    Great!

    I feel even more encouraged now. We do get several weeks of down to -10°C to sometimes -20°C here from mid- January to mid-March, but not always. Last two years, we had no proper winter here but +12°C on Christmas day and New Year's eve, also up to 37°C in the summer with strong storms and excruciating humidity - it felt as if we'd been transplanted to the Philippines. Somehow, over the last five decades, the weather pattern has changed significantly, with many oddball seasons that don't seem to belong here.

    Reason why I'm so finicky is that I dream of keeping these trees for so long that my children can each take one with them, once I'm no longer there.
     
  8. Keke

    Keke Active Member 10 Years

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    Just keep an eye on the projected temps and you'll be fine. If it looks to go down overnight to -10C or greater, just move the pots as close to the building as you can if they are not already there. People underestimate the amount of ambient heat radiated by a building. The burlap will hold snow, if any, which is good -- snow is a great insulator. It will also keep the wind from drying them out too much. Don't cover the tops of the trees with the burlap, so if the weather is good they can "breathe." Best case scenario, the soil is damp but not wet before a freeze -- in fact, that's a good rule of thumb for everyday, not just before a freeze*. A dry plant handles cold less well than a moist one, but a wet pot will just turn to a ball of ice, which is bad too. You might wrap the pots themselves in bubble wrap, as maplesandpaws suggests. That keeps the temperatures from spiking on a sunny day and perhaps cracking the pots.

    * You asked about watering during dormancy. It's almost exactly the same as during the obvious growing season. Remember they might be growing roots anytime it's above zero. As long as the pots drain well, cut back on the watering so they stay just damp on the soil surface. Don't water to a schedule, because plants have no idea what day it is. They only know the environment they're in. Get into the habit of checking them every couple of days, or more often if it's been windy. You'll quickly get a sense of when they need water and when they don't.
    Have fun!
    Keke
     
  9. Rosy_S_Cenario

    Rosy_S_Cenario New Member

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    Thanks again!

    I'll try to keep the soil damp and leave the pots as close to the window/wall as possible then, wrapping the pots with some burlap.

    One more peculiarity(?) I almost forgot - apart from the leaf-tip/edge browning issue, I was wondering that throughout autumn, the leaves hardly changed their colour at all - practically no orange, red or deep brown colour change, only a "tired" green that lost saturation and became yellowish until the end of October, while leaves were dropping - is this also an issue of my plants having to get accustomed to a new pot, new soil and of course a new location?
     
    Last edited: Oct 31, 2016
  10. Keke

    Keke Active Member 10 Years

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    Our newest maple didn't colour up the first year either, so it might be a "change" thing. But usually colour has to do with temperatures and day length. Some years we get wonderful colour out of our native vine maples and some years, nada. Just what you've seen -- dulling down, then they drop. We seem to get the best colour with a larger variance between day and night temperatures, so when we get a clear stretch in the early fall, it seems to help. So maybe your weird weather this year is partly to blame! Don't worry about it too much, but if you want fall colour don't move the pots to next to the building too soon in the fall. They'll get more temp variance away from the building.
     

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