How to water large trees

Discussion in 'Plants: Science and Cultivation' started by Margot, Jul 12, 2021.

  1. Margot

    Margot Generous Contributor 10 Years

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    A discussion has been going on lately under -
    Oak Tree
    Latest: Alesig, Today at 5:00 PM
    Pacific Northwest Native Plants

    Some comments have raised questions for me that don't really have anything to do with the question @Alesig was asking about leaf problems on his oak tree. So I thought a separate thread would be a good idea.

    I 'd like to know more about watering large trees. From what I've read, many large trees, like oaks, grow long tap roots to access water deep underground. Some sites say that trees grow most of their roots within the top 18 inches of soil and derive most water in that zone. How much does artificial watering help in the long run?

    It's obvious when you see boulevard trees languishing that the water bags placed by their trunks must do at least some good helping them survive. I wonder though about their long-term survival.

    What I notice here in the very dry area where I live is that young trees may grow happily for many years but eventually their water needs exceed what is available naturally. This is becoming ever more evident as the climate changes.
     
  2. Georgia Strait

    Georgia Strait Contributor

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    Does the old maxim « everything in moderation » apply?

    But you know - the big old cottonwoods along the River banks and lakeshores seem to tolerate the spring freshet / floods ... then dry summers and low water (frozen) shorelines

    Does our shared fav Dr Linda from WSU have any info about this?
    Linda Chalker-Scott | Washington State University
     
  3. Acerholic

    Acerholic Paragon of Plants Forums Moderator VCBF Cherry Scout Maple Society

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    Good morning Margot and Georgia, this is an interesting topic and especially what BC is suffering atm.
    I would like to add that I water my older trees especially in the Spring, as we suffer very dry periods at this time these days. When I didn't do this several years ago, I had many trees suffer badly. So I decided I would not do this again.
    The next point is that in 1976 here in the UK we had a heateave and many older trees where I live and in the local woodland defoliated and died.( all species btw). So this suggests that even trees that have been in the ground more than a few years need some help. Of course in nature trees will die off and others will survive. But do we want that in our gardens of our loved specimens. Frankly I do not and I will continue giving them a drink when needed for the rest of my life, no matter what anybody says differently.
    Is that me not being flexible and going with the science. Perhaps it is. But the trees in my garden will not become stressed again due to lack of water.
    I hope that didn't sound to bullish, I didn't intend it to be.

    D
     
  4. Georgia Strait

    Georgia Strait Contributor

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    @Margot - I was scanning thru our shared fav Dr Linda C-S at WSU

    AND re-read thé article about summer watering (hot weather watering myths) - link below

    I like this phrase ...

    “suboptimal plant-water relations”

    It amazes me the unique and precious combination of factors that work together to create successful (ideally non invasive) flora fauna ecosystems

    PS - how come it’s impossible to underwater knotweed and broom :)

    https://s3.wp.wsu.edu/uploads/sites/403/2015/03/leaf-scorch.pdf
     
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  5. Margot

    Margot Generous Contributor 10 Years

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    I agree!

    A sentence in Linda's article put my mind to rest about having perhaps caused leaf damage on my rhodos this year with early spring fertilizing:
    "Some studies have found additional nitrogen helps prevent leaf scorch (perhaps by increasing root growth and uptake capabilities."

    What would LC-S say about this advice from an acquaintance of mine is South Australia? What do you think?
    "We had a mild summer with only one day reaching 40. There is a product here that we use to help our tender plants survive. It is an anti-transparent that is sprayed on to conserve moisture. Here it is used by commercial growers to protect seedlings etc. It is also useful against mild frost."
     
  6. Margot

    Margot Generous Contributor 10 Years

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    Georgia Strait likes this.

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