Magnolia Grandiflora having some mold, fungus (??) problems

Discussion in 'Magnoliaceae' started by ose, Mar 15, 2008.

  1. ose

    ose Member

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    Hi

    I planted a Magnolia Grandiflora on my front lawn last spring (2007). I've noticed this March that the leaves/stems have blackish/brownish spots on them. Some leaves are completely covered with the stuff.

    Any ideas what is happening (not normal I presume)? Any ideas on how to treat/fix?

    Thanks
     

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  2. plantenthusiast

    plantenthusiast Active Member

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    ose,

    Now I am not sure, but I thought I'd give it a shot as no one else has yet.

    It could be bacterial leaf spot (you can check the photos on at the bottom of this link, and see the recommendations):

    http://www.mobot.org/gardeninghelp/plantfinder/IPM.asp?code=185&group=8&level=c

    However, I think that it looks more like anthracnose. If so, then you should clean up all fallen leaves and twigs in Autumn and prune out any dead branches and dispose of all of these.

    Also I saw the grass in the photo and wanted to ask whether there is grass growing right near the base of the tree? If I am not mistaken, magnolias often have shallow root systems and this grass should be removed. An arborist once told me that if a tree is doing poorly, the first thing to do is remove the grass around the base of the tree, and top dress or mulch; often it would perk up in no time.

    By the way, have you tried posting in the magnolia forum? Best of luck with your tree,
     
    Last edited: Apr 13, 2008
  3. Ron B

    Ron B Paragon of Plants 10 Years

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    Often when broadleaf evergreens become spotty the soil is too moist for them. Your tree also has poor color (not very green) as do many southern magnolias in this climate, a tree can be green and still have a deficiency so when the color is this poor things are pretty bad. I suspect part of the problem is cool winter soils becoming low in nitrogen, otherwise many sites here probably have an inherently unsuitable fertility level for this species native to rich bottomlands in a hot climate.
     
  4. ose

    ose Member

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    Thanks for the responses. I am in Victoria BC.

    I will remove the grass around the base of the tree as it sounds like a good thing to do irregardless if it is causing the problems. Would this also help with moisture; as Ron B suggested it may be too moist in the Winter? There are other evergreen Magnolia's growing in my neighbourhood and they seem to be doing just fine. Same types of lot, same amount of rain.

    One other piece of information, I went back to the nursery which sold me the tree and found others there with similar spots on the leaves -- they were still in pots but not in nearly as rough shape. So my tree may have had this problem before I even put it in the ground.

    The 'destruction' of my tree seems to have slowed with the warmer drier weather. There is new growth starting and I'm curious to see if it gets the spots as well.

    (where is this magnolia forum? here are UBC forums?)

    ose
     
  5. Ron B

    Ron B Paragon of Plants 10 Years

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    If the nursery has a return policy allowing it maybe you can still take it back. They shouldn't be comfortable selling you diseased stock.
     
  6. plantenthusiast

    plantenthusiast Active Member

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    ose,

    The magnolia forum is in the UBC Forums; if you go to the main garden forums page and scroll down to 'Plants by Taxonomic Groupings', it is listed as The Genus Magnolia.

    Also, as Ron B. pointed out, you could return the plant to the nursery. You could also take a few leaves in to that same nursery, explain your situation, and ask if they have any advice, or can possibly offer you a replacement plant or some other form of compensation.

    I lived near there too, so I know that Magnolias do thrive there, although I am not certain about that particular species (Southern Magnolia), as you have seen elsewhere in your neighborhood.

    In regards to wet winters, do you have it planted in a well drained site?

    Hope that all goes well with your Magnolia!
     
  7. ose

    ose Member

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    plantenthusiast and Ron B

    Thanks for the tips and information. I think my tree is a Grandiflora. The others in the neighbourhood might be "something gem", "brown gem" or something. They are still evergreen but the leaves are not quite as big, a little browner on the underside.

    I could probably go back to the nursery if I had the receipt.

    ose
     
  8. Ron B

    Ron B Paragon of Plants 10 Years

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    'Little Gem' is very commonly planted.
     
  9. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    (I've moved this thread directly to the magnolia forum)
     
  10. Joce

    Joce Member

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    My grandiflora has the same leaf spots. I have read and been told by garden centres that the problem is common and to make sure to collect any fallen leaves and debris. I am told it will not kill the tree.

    The tree is within a few feet of two other healthy grandifloras in a townhouse courtyard. They are roughly 25' high and lovely.

    Question: Will the spot problem spread to the other trees? Will the problem continue to disfigure the leaves indefinitely?

    Bottom line is should I remove one tree to save the other two?

    Thanks for your input.
     

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