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Rescue me! Maple leaves withering and turning black

Posted by boo_lala 8 TX (My Page) on
Fri, Mar 24, 06 at 23:20

(Sorry: I posted this first in the gallery because I thought I could only attach pictures there; but I've attached links to the pictures here).

Help!

Some friends of mine left me a bunch of their plants when they moved, including two young Japanese maples in pots. One is a Bloodgood (it still has the label) but I don't know what the other is. The mystery maple is the one with the problem.

A couple of weeks ago the leaves started to sprout and it was looking great--bright green leaves with a slightly reddish border. Then suddenly some of the leaves started to wither and turn an ashen black.

Is this a disease, a parasite, or something I did wrong? (I am very new to any sort of gardening)

Could it be from too much water? We had very heavy rains last weekend (3 inches in 3 days). Before that there was drought (although I'd been watering it). It's also been a bit cold here the past few nights (but above freezing) and very hot before that (highs in the 90s). Could the pot be too small?

If it's a disease/parasite, will it spread to the other maple (which is on the other side of the house) or the other plants? Is there anything I can do to save it?

I will try to attach pictures, but I apoloize in advance; I took them at night.
with pot
black leaves
another limb


Follow-Up Postings:

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RE: Rescue me! Maple leaves withering and turning black

  • Posted by tapla z5b-6a MI (My Page) on
    Sat, Mar 25, 06 at 11:16

The soil appears poor and compacted in the first photo. The tree needs repotting badly, but to do so now would likely kill it. Even those experienced in out of season repots would be reluctant to repot now. You can plant out and lift & repot next spring, or plant entire container & repot next spring. Both of these options are better than potting up, as you'll create dissimilar soils in the container & one soil will always be too dry and the other too wet.

Al


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RE: Rescue me! Maple leaves withering and turning black

Appears to be a rather stressed specimen of coral bark maple, 'Sango Kaku'. These are rather prone to pseudomonas, specially under stressed or excessively wet conditions. Pruning out affected portions (disinfect pruners after each cut) can retard development and spread, but this plant should be out of the pot and in the ground to reduce stress. I'd also be concerned about the unfavorable growth pattern of the limb that is twisting around the main trunk - if this tree survives, that will only be a continuing problem down the road. I'd remove it now while the tree is still quite juvenile.


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RE: Rescue me! Maple leaves withering and turning black

Thank you both for your responses!

tapla--I'm going to have to study your comment; I'm such a novice that I don't even understand the terminology you used (plant out vs plant up). But it sounds like I shouldn't do it this season anyway.

gardengal48--Do pseudomonas put my other plants at risk, or are these bacteria present everywhere and only susceptible plants get them? I don't think it would be difficult to remove the twisting branch, as it does not have much growing on it. On the other hand, it seems like every single branch has some healthy leaves and some withered leaves; it's not limited to one area. Should I remove just the withered leaves at their stalks? And how would I best disenfect the pruners? Do they even make pruners that small?

I apologize for the questions. (I told y'all I was a novice.) I guess maybe I should just hire an arborist to see if it can be saved.

Thanks again for your help.


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RE: Rescue me! Maple leaves withering and turning black

  • Posted by tapla z5b-6a MI (My Page) on
    Sat, Mar 25, 06 at 18:52

"Plant out" (in the ground) is what Pam suggested & is your best bet. Potting up is simply moving the plant to a container of greater size & soil volume. I should also have mentioned the limb entwined around the main stem - Pam is, of course, right in suggesting you remove it in the near future.

She knows her stuff, so perhaps she can suggest a suitable fungicide, other than the Bordeaux Mix I would use - if you're of a mind to use one. Trees that are not stressed are usually able to defend against this bacteria, another reason to get the plant in the ground where it can recover some vitality.

Al


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RE: Rescue me! Maple leaves withering and turning black

It's a bacterium that's pretty difficult to control. Rather prevelent here in the PNW as our weather is an ideal environment for the pathogen and it can decimate a good number of nursery crops. Recent studies by OSU have shown that there are numerous variations of the pathogen and that many strains have developed resistance to the typical controls, usually copper or streptomycin. Copper, like the Bordeaux mix, is likely your best chemical control or a similar product like Microcop. Application should be begin in fall and again early in the season before budbreak. It is likely too late to apply now that the tree is in leaf - J. maples are rather sensitive to sprays on their foliage and copper in particular can cause a phytotoxic reaction.

I would remove the blackened foliage and trim back any leafless portions to a healthy node. Watch for stem discoloration and as you see it, prune out below it. (And yes, good pruners come in all sizes :-)) Disinfect the pruners with something like rubbing alcohol or bleach - Lysol spray is popular at my nursery. Plant it in a good location as soon as you can and keep an eye on it. A young tree in decent growing conditions could outgrow it, but nothing is guaranteed.


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