Please help us identify the problem and advise how to help this tree

Posts

• Fire Posts: 19,096

  April 2018

  It looks like it could be caterpillars making the holes. The brown mottling could be leaf spot.
  

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• Obelixx Posts: 30,090

  April 2018

  We inherited a small, weak, neglected, sickly looking magnolia in this garden when we moved in 18 months ago.  I watered it with rain water, poured a whole bag of ericaceous compost over its roots and had a gentle word with it.  It then got more ericaceous compost in December and again in March.   Last spring one branch flowered well and the rest followed slowly and sporadically and then foliage followed, some of which got chewed like yours has tho I found no culprits.  
  
  Late this winter I put cheap wooden edging round it so I could pour on 6 more bags of ericaceous compost and some pelleted chicken manure over a bigger root area and not have it all fall or blow away while it settled.   I have filled this extra depth with spring bulbs from containers and, once these have all died back, it will get another feed and a mulch of chipped bark after replacing the wooden edging with stones.
  
  This spring it is full of flower buds all opening at the same time in the last day or so.  It remains to be seen how well the foliage does but clearly it is in much better nick this year.  I have put bird feeders nearby to attract birds that will, with any luck, eat the leaf munchers if they return.  Fingers crossed.  I don't use sprays.

  Vendée - 20kms from Atlantic coast.
  

  "The price good men (and women) pay for indifference to public affairs is to be ruled by evil men (and women)."

  Plato
  

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• Dovefromabove Posts: 88,147

  April 2018

  @Obelixx ... do you happen to know whether magnolias get Shot Hole disease?  It looks quite like it in some ways but I can't find any reference online to it affecting magnolias. 

  
  Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
  
  
  
  
  
  

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• Borderline Posts: 4,700

  April 2018 edited April 2018

  I think the leaf in the photo looks to be in advance stage of either Fungal Leaf Spot or Bacterial leaf spot. Fungal leaf spot can be passed through rain and wind in dense cover and crowded branches. Excess moisture and leaves that have collected around the base of the tree may have helped to spread and re-infect. 
  
  If it's Bacterial Leaf Spot, check for any cankers/wounds or other entry points like cracks in the branches. It's a bit more rare, but also possible, it all depends on the health of branches and trunk. Again, once infected, the tree will weaken and the leaves will start with spots and then they grown larger enough to create holes. 
  
  In both instances, you need to prune off some of the branches to create air flow and minimise the dense branches where leaves are crowded. A tree growing in too much shade may cause the issue again, so it's important to thin out if it is planted in quite a shaded area. Start collected and raking away any fallen leaves straight away. Good hygiene is needed, so all blades used must be cleaned well before and after pruning.
  
  
  

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