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kjmm1

Yellowing of Interior Leaves of Mikawa Yatsubusa

kjmm1
9 years ago

Hi All,

New around here, and I've caught the JM bug.

I just bought my first house two months ago, I am in zone 9 (Southern California) I'm a total newb to JM's and gardening, but a month ago I started collecting JM's.

My favorite JM in a container, a 4-5 ft mature Mikawa Yatsubusa just started to show some yellowing of interior leaves that crisp up then fall off.

It it happening to only the interior leaves and on one side (the side facing away from my house). There hasn't been a lot of this, and it's just been for the past few days, but if it is something, I want to catch it early and do something about it before it gets worse.

There was none of this for the previous month that I've had the tree, all of the leaves were deep green, new growth was light green. I had it on my patio with about 30% shade and most of it protected from afternoon direct sun (some of it got direct afternoon sun but was not burning. I was watering it every few days, only when I noticed the soil starting to get too dry.

Then we had a heat wave a week ago combined with Santa Ana Winds (hot dry strong winds), and I saw some LEAF scortch... I wasn't sure if got wet from the sprinkler in the morning and it got hot too early and burned the leaves, or if it needed more water, or if it needed more protection from the direct afternoon sun, the hot winds, or that fact that it wasn't mulched, or if it needed fertilizer, so I did all of the following:

- I watered it everyday (during the heatwave and low humidity my plants needed it badly... water was evaporating a mater of hours elsewhere in my garden)

- Added mulch (but still a few inches away from the trunk)

- Moved it to a shadier spot on my patio that gets 60% shade.

I noticed no new burn or signs of stress for the rest of the heat wave.

Once the weather became mild again, I checked under the mulch and saw a number mite-like bugs! Ahh!!! I got rid of the much and replace the top half inch of soil with acidic soil. Well, actually I sent DH out for the acidic soil and he came back with Miracle Gro African Violet mix (he told me they didn't have the normal azelea mix I use and that the guy told him this was the same stuff).

I believe they ended up being just spring tails (they've been gone ever since)

Anyway, it was a day after that that I noticed the yellowing interior leaves.

I was worried it was for the violet mix... but the amount I used was incredibly minimal, only two handfulls at most. I didn't think it could be fertilizer burn, there is SOME fertilizer in the mix but not much. And I haven't read anywhere that fertilizer burn looks like that. There weren't that many little fertilizer balls in there either....

There aren't any other leaves doing this on the outer areas or at the buds, or new leaves unfurling, etc.

These pics are taken from the inside of the tree, looking up.

Is this normal...or is this something to worry about?

There is an article online that says yellowing on the interior leaves of a JM is zinc and manganese deficiency.

I am super scared to fertilizer since I know JM's are sensitive to it.

Or am I just paranoid and this is normal?

Pls help!

Comments (6)

  • kjmm1
    Original Author
    9 years ago
    last modified: 9 years ago

    Another pic

  • kjmm1
    Original Author
    9 years ago
    last modified: 9 years ago

    Another pic

  • kjmm1
    Original Author
    9 years ago
    last modified: 9 years ago

    I meant to say the new buds and new leaves unfurling are normal, light green colored.

    My main worry was that this is some kind of deficiency, or an issue caused by the violet mix, or something else, or nothing at all?

  • jean001a
    9 years ago
    last modified: 9 years ago

    Looks like only a few interior leaves are affected.
    If so, I suspect it's a response to the earlier hot, dry santana winds.
    Considering SoCal's general conditions, I'd say your JM is doing very well.

    Jean,
    who previously gardened for 30-some years i LB, CA

  • kjmm1
    Original Author
    9 years ago
    last modified: 9 years ago

    Thank you, Jean! Oh thank goodness, I'm so obsessive and neurotic about my hobbies, this being my latest and most complicated one, I constantly check on my plants and am always worried everything little thing is something.

    Every bug, every mark, every change I see in my trees I google and obsess about and worry, lol.

    You gardened in LB, CA for 30 years, do you mean Laguna Beach or Long Beach? Did you have JM's out there? Do you have any tips for me?

    I have have purchased 11 JM's so far, 3 of which are specimen sized and the rest medium and 1 sapling, and I am about to have 10 more delivered (6 of which are specimen sized). I've contracted the JM addiction something fierce and I want to make sure they don't die or decline on me.

  • gardengal48 (PNW Z8/9)
    9 years ago
    last modified: 9 years ago

    I agree with Jean - a perfectly normal reaction to a stressful weather situation.

    While Japanese maples are pretty easy to grow and do not usually have a lot of problems, growing them in SoCal can be a challenging undertaking. That is a climate they are not overly fond of. I'd only recommend them for coastal communities, with adequate protection from intense afternoon sun and out of heavy winds (ie, Santa Ana's). And watch out for alkaline irrigation water and compensate for this appropriately.

    Other than attending to these issues, for your own sanity, don't sweat the small stuff :-) The loss of a few leaves, a little insect activity is NBD. If a LOT of crisping or leaf loss and you see major leaf damage from insects, then you can start getting a little concerned.

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