Mountain ash sudden collapse

Discussion in 'HortForum' started by sgbotsford, Jul 27, 2019.

  1. sgbotsford

    sgbotsford Active Member 10 Years

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    Sold this this tree this spring and it was doing well. Client planted it and it showed new growth, and seemed happy it it's new location. Then in less than a week, it has gone yellow, new growth is drooping. No obvious signs of fireblight -- tips not going black, no ooze etc. No other trees are affected. Neighbour applied curtail to their own yard, but that's not close to the tree. Lawn has been fertilized, so there will be some run off.


    Ideas?

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  2. Sulev

    Sulev Well-Known Member

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    Maybe the client just forgot watering, because it was quite a few rainy days in your area, and the client was hoping, that watering by rain will be sufficient?
    ACIS Weather Station Data Graph
     
  3. Sundrop

    Sundrop Well-Known Member

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    I am curious, what is this red stuff at the bottom in 1st pic?
    And what do you mean by "curtail" ?
     
  4. Ron B

    Ron B Paragon of Plants 10 Years

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    Somebody needs to dig around inside the original field- or potting soil mass and check for dryness. On another subject if it happens to be this variety

    https://www.monrovia.com/plant-catalog/plants/2105/coralfiremountainash/

    - which it seems in the picture with the fruit to resemble - I wonder about it being adapted to the year-round climate of Alberta anyway. Also in addition to fire blight perhaps borers are possible there as well, I don't know. Either of these banes by themselves are enough to make susceptible trees a bust as decorative features in areas where they occur.
     
    Last edited: Jul 27, 2019
  5. sgbotsford

    sgbotsford Active Member 10 Years

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    We have had well over two inches of rain during the last month. I have two of these in my demo garden. They are doing fine. The client has verified that soil moisture is good. Had it been a water shortage I would have expected it to show up long before this.

    The ash overwintered here for 2 years before going to it's new home.

    Usually the problem in our heavy clay soils is over watering, not underwatering.

    The Monrovia article isn't helpful, as you need to balance the potential evaporation/transpiration which is temperature and humidity dependent. Remember that in Alberta 26 is a hot day.

    The ones at my farm currently are getting about a gallon a day from a drip irrigator in a #7 pot.

    ***
    Curtail is a weed killer. Active ingredient: Clopyralid
    ***
    The red stuff at the base of the tree is either red shale, crushed brick, or dyed wood chips. All are used locally as cosmetic mulches.
     
  6. Sulev

    Sulev Well-Known Member

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    Those two and a half inches of precipitation came in 18 parts, there was no rain exceeding 18 mm a day. Such a small quantity may not even penetrate the mulch layer (dry wood chips can absorb and hold lots of water) under the crown, and if the soil is clay and a small hill was formed on top of the planting hole, then the water penetrating the mulch layer may flow away from the root area of the planted tree. The tree was planted in a bare area, open to the sun and to the winds. The crown/root balance is most probably favourable for drying. There was long period between July 8 and July 18 where there was no significant precipitation (less than 5 mm a day, 1 mm as an average per day), but temperatures were around or even above 25 degrees C. On July 18 there was 24 mm deficiency (-36%) of cumulative precipitation compared to the long time average of July. The tree looks to me like it just dried, no disease or pest symptoms.
    On clay soils plants can't obtain all the water from the soil, even if the soil seems still slightly moist, because water is so strongly bonded with clay particles.
    If the ground water level is not high there, and the client did not water the tree, I still consider simple drying at summer heat the most probable cause.
     
    Last edited: Jul 27, 2019
  7. Sundrop

    Sundrop Well-Known Member

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    The problem could be compound: the tree planted root bound, herbicide drift, and some toxins in the red mulch.
     
  8. Margot

    Margot Generous Contributor 10 Years

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    Notwithstanding the excellent points made by Sulev regarding the possibility that the tree was not receiving enough water, you have to wonder how the surrounding lawn could be so healthy and green while the tree died of drought. After 10 days with only 1mm precipitation per day and a temp of 25C, most lawns would be looking stressed, wouldn't they? What I'm wondering is if there may have been more rainfall in that particular area or if there is another source of water - either way, wondering if a lack of water really is the problem.

    It would be worth looking at the roots as Sundrop suggests and seeing if they may be girdled or rootbound.
     
  9. sgbotsford

    sgbotsford Active Member 10 Years

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    I've got more inquiries going there.

    Client is going to dig into the root ball. And I want to know more about the red mulch.

    You must remember that overall this is a dryland agriculture region. The native ecozone is "Aspen parkland" A complex meta-stable mix of aspen, spruce, and grassland in a dance of fire succession and a decade long drought/plenty cycle. The long term average precipitation per year is ~18" (350 mm) but there is a 50mm standard deviation on it. Typically there is a decade of 15" precip and a decade of 20" precip.

    Soil and subsoil is very heavily clay and silt based. This gives a lot of water storage capacity for the soil. Grass here typically slows it's growth to needing mowing only every two weeks by August. This year in the aisles in my tree farm I'm mowing once a week, and taking enough off at a pass that the engine of my 25 HP diesel mower is bogging down at normal cutting speeds. Farmers in their crop planning consider precip for the previous 5 years -- and measure subsoil moisture to depths of 12 feet. The soil particle size as small as silt, there is a lot of movement by capillary action.

    The picture below illustrates: This was taken at the end of August 7 years ago. The lawn, while browning is still somewhat green.



    AugustGrass.jpg
     
  10. sgbotsford

    sgbotsford Active Member 10 Years

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    Client confirms root ball is moist.

    In passing: The usual pattern I've observed for deciduous trees under drought stress is the premature senesence of individual leaves, then individual leaves losing turgor. On a tree larger than a seedling I've not yet seen it happen in this short a period of time.
     
  11. Sulev

    Sulev Well-Known Member

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    I have seen trees of that size drooping their shoots and leaves only after 5 to 10 km of ride in the open cargo bed of a pickup truck for transplanting into their new location.
    But if the client confirms, that moisture was not an issue, then maybe the root flare was planted too deep?
    Mountain ash is quite a vigorous plant and can withstand heavy pollution in cities. Can't believe, that some fertilizer or tiny amount of herbicide could kill it so quickly.
     
  12. Ron B

    Ron B Paragon of Plants 10 Years

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    Did the customer check well inside the material around the transplant? If they only did a superficial inspection that did not establish that the entire volume of soil or medium is moist.

    Specimens grown in coarse potting medium then later planted in fine textured existing soils, without being bare-rooted before installation on final planting sites will often be subjected to the material immediately around them shedding water to the surrounding unmodified native soil during periods of less than ample moisture availability. This is due to fine textured soils having a greater attraction for water than coarse ones. This phenomenon may even operate during rainy winter periods, with retained potting soils immediately around planted specimens not remaining moist during those times also.

    Amending of planting hole backfill during planting adds an additional zone of material around the plant which will be subject to recurring dryness, when the soil around the hole is finer textured.
     
  13. sgbotsford

    sgbotsford Active Member 10 Years

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    I may have to make a site visit.

    The red mulch is actually one of those recycled rubber products. Client says they have used these on other trees.
     

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