Red robin ornamental tree struggling

Discussion in 'Pests, Diseases and Cures' started by Bart, Jul 11, 2019.

  1. Bart

    Bart Apprentice Gardener

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    Hello everyone,

    I do appreciate if someone cloud help us out with our red robin struggle.

    We have got three red robin trees planted in pots (approx. 0,5x0,5x0,5m) with approx. 10cm os pea shingle at the bottom for drainage. The trees arrived in Spring 2 years ago and suffered badly from black spot during first winter but bounced back nicely after heavy pruning. Last winter the problem occurred again (black spot I think) but in a slightly different form i.e. leaves were turning black-ish without the apparent spots that followed later. As new shots came out in spring I kept removing the sick looking leaves hoping for recovery. Soon the new red leaves started to dry out as if they were burnt so I decided to prune it hard (June). It seemed that the plants started to bounce back with new small tiny leaves and branches but now when the fresh red leaves got bigger they turn rusty red and look poorly. I do appreciate if someone could advise on how to treat our robin trees as they are beautiful plants and we are not great fans of throwing plants away when sick.

    The trees were treated with Rose Clear insecticide/fungicide couple of weeks ago when were attacked by aphids.


    I hope the pictures will add some clarity.


    Your help is much appreciated.


    Regards,
    IMG-20190710-WA0011.jpgIMG-20190710-WA0012.jpgIMG-20190710-WA0013.jpgIMG-20190710-WA0014.jpgIMG-20190710-WA0016.jpgIMG-20190710-WA0017.jpgIMG-20190710-WA0018.jpg

    Bart
     
    Last edited by a moderator: Jul 11, 2019
  2. lolimac

    lolimac Total Gardener

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    Hi Bart and welcome to GC...:dbgrtmb:..

    I think it's just a trait with Red Robins mine gets it too but I do nothing and it seems to sort itself out.I think the 'blackspot' is like a sooty mold isn't it...If they are containerised are they getting enough water ?..Is it possible to plant them in the ground ?..if not I'd keep them moist but not too wet..If you can get them in the ground I'd give them a feed of bonemeal to help them along.:dbgrtmb:
     
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    • Bart

      Bart Apprentice Gardener

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      Hi lolimac,

      Thanks a lot for your response. It looks that red robins are fairly sensitive. There seems to be no signs of blackspot at the moment (at least no black spots on the leaves as last year in the winter). They just start to turn rusty-ish red following spotty/veiny pattern. I fed them with blood fish and bone after pruned hard and they started to bounce back nicely. Unfortunately now the rusty problem attacked.

      Don't know, possibly the pots are too small? Drainage works well as excess water drains through holes drilled in the bottom of the pots. Puzzled completely..

      Regards,

      Bart
       
    • Mike Allen

      Mike Allen Total Gardener

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      Gardeners and Blackspot. Probably thoughts turn to Roses and blackspot. However other plants can also be come victim to this fungal attack. Firstly, if you are aware that your plant is susceptible to this enemy, then don't wait until you have visible signs of an attack. Spray/treat the plant with a fungicide possibly prior to leaf bud break followed by frequent treatments. Depending upon the intensity of the infection, infected leaves can easily be picked off and burned. DO NOT COMPOST. The fungus will survive in the soil and multiply, fallen leaves should be quickly gathered up and burned. When spraying, a good soaking of the soil close to the plant can help.

      It may be of help to gardeners to, prior to buying/obtaining certain plants, to ceckif that plant may be susceptible to fungal diseases. Yes a plant that really continually gets hit hard by blackspot, sad to say may need to be destroyed poste haste. I imagine WOO will agre with me, when perhaps a cherrished rose is the victim, this can be a hard choice.
       
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      • Bart

        Bart Apprentice Gardener

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        Hello Mike,

        Thanks a lot for your response. I have only now noticed it now. Unfortunately, the disease struck again this year. Any chance you could recommend any good product available to treat the gardener's fungal disease. Looks that Maconzeb, that is apparently very effective, is not available to amateurs but only to farmers etc...

        Thanks,

        Bart
         
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        • Mike Allen

          Mike Allen Total Gardener

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          Hi Bart.

          Many trees and shrubs are being affected. Perhaps it's due to the weather and climate change etc. I have to be honest. Having been retired for a long time. I very rarely resort to chemical use. In some gardening circles, I am at times called. The surgeon. My own reason is that once your plant is infected, the best and most cost effective method is to remove the offending part. Thanks to the EU many gardening and horticultural aids were banned. There are several sprays and powders available though. It's just a matter of searching the list. Sorry for my lack of assistance.
           
        • pete

          pete Growing a bit of this and a bit of that....

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          Not sure what the problem is, bright red new growth which slowly turns green, but still with a red tinge.

          What are the strange pots, never seen them before.

          They haven't got many leaves, are the pots big enough.
           
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          • Bart

            Bart Apprentice Gardener

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            Hi Mike,

            Thanks for getting back to me. I pretty much agree with your surgical approach. The trees have been pruned hard in the winter and bounced back nicely. Powdery mildew set in in spring so again the affected leaves got removed and again the trees bounced back to suffer from the fungal infection maybe 5 week later. So frustrating. If don't find some effective fungicide I will have to destroy them with heavy heart along with the pots I suppose...

            Thanks,

            Bart
             
          • Bart

            Bart Apprentice Gardener

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            Hi Pete,

            The pots are approx 0.45m cubes with make-shift covers to keep excess rain in the winter away. The trees are approx 1.4m tall above the pot. Do oyu think that the pots might be to small as well?

            Thanks,

            Bart
             
          • Mike Allen

            Mike Allen Total Gardener

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            Regarding the pot size. Hold the plant at it's base, soil level. Lift and tap the pot off. The roots will tell their own story. For instance. If as all as you can see is roots, then the pot is too small. A healthy plant, potwise will display the compost and an evenly balanced root system.

            I find 15Ltr. pots ideal for potted shrubs etc. Pot sizes above that become too heavy to move about. Actually there is so much that can be learned from, now and then taking a look at the rootball. Apart from re-potting (moving up a pot size or two) Sometimes a gentle teasing away some of the compost, or even going as far as basically transforming your plant to what really is a bare root, then planting in fresh compost. During this process, a bit of root pruning can be done. This basically involves, cutting back some of the main root, the thick woody roots. Hope this helps.
             
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            • pete

              pete Growing a bit of this and a bit of that....

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              Just my thoughts but if the pots are well enough drained the winter wet won't be a problem, this is a pretty hardy plant and survives well.

              Just wondering if they tend to get too dry at times.
              They are naturally a big plant and fairly hungry so regular liquid feeding would be better than blood fish bone which is slow reacting.
               
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