How to rid these crunchy brown spots on my teddy bear magnolia?

[mandy123]

  

My 4 year old teddy bear magnolia has recently started spreading a brown crunchy leaf and it seems to be spreading quickly. Someone from bunnings told me it was frost damage but I don’t think this is the case … do you think it is fungal and needs to be treated that way? Any help and advise us appreciated! 

 

[MitchellMc]

Welcome to the Bunnings Workshop community @mandy123. It's terrific to have you join us, and many thanks for your question about Magnolia care.

Your teddy bear magnolia may be dealing with a fungal issue, especially if the brown, crunchy leaves are spreading quickly. While frost damage can cause similar symptoms, it typically affects new growth and doesn’t spread rapidly across the plant. Fungal infections, such as Cercospora or Anthracnose, are common in magnolias and could explain the symptoms you're seeing. 

Watering and drainage could also play a role, as overly wet soil or poor drainage can stress the roots, making the plant more vulnerable to fungal problems. You might want to check whether your magnolia is sitting in waterlogged soil, which can lead to root rot or similar issues. It's also worth considering whether your soil is compacted or lacking nutrients, especially if it’s clay-based, as this can further weaken the plant.

To manage the problem, you could apply a fungicide like Yates Liquid Copper Fungicide, which is effective against many common leaf diseases. Make sure to prune away any affected leaves or branches and dispose in hard rubbish to prevent the fungus from spreading, and always sterilise your tools between cuts. Improving airflow around the tree by avoiding mulch buildup near the trunk and addressing any drainage problems can also help the plant recover. If the issue continues, or if you notice other signs like trunk damage, it might be worth consulting with a local arborist for further advice.

Let me tag @Noelle to see if she has any thoughts.

Please let me know if you have any questions.

Mitchell
 

[Noelle]

Hi @mandy123 

Mitchell's given you some terrific information and advice! In addition to his potential diagnoses, may I throw into the ring that, in my opinion, the crunchy brown spots look similar to sunburn!

Is it possible the foliage has been wet on quite bright sunny days? The spots look very like the type of damage that can be caused by sun through water droplets.

Wherever possible, try to keep the leaves dry (apart from when it's raining, of course!). When the tree needs watering make sure the hose or irrigation is aimed at the soil over the root system, especially when the sun's out.

Treating the plant for a possible fungal infection is a good move, better done sooner rather than later too.

[mandy123]

Thank you so much for the advise. I have pruned all the affected leaves away and will treat with liquid copper this evening when the sun goes down. Hopefully this spring it will reshoot as it looks very bare now sadly.