How to treat Viburnum with brown spotted leaves?

[ajb173]

Hello! We have a run of viburnum trees. Approx 12 trees over 12 metres and they are now about 4 metres high. About six months ago, after a large prune, we noticed one of the bushes leaves started to curl. Now on a few other bushes, the leaves have brown spots. I'm having quite a hard time working out if the cause is a fungus or a pest. Any tips appreciated. Thank you

    

 

[JacobZ]

Hi @ajb173,

A warm welcome to the Bunnings Workshop community, and thank you for your question.

It seems likely that the issue is related to either fungus or pest problems.

Inspecting the soil at the base of the tree will likely reveal some answers that we can turn into a plan.

Can I ask you to upload some photos of the base of the tree, as well as inspect the plant for signs of insects or insects themselves?

Allow me to tag @Noelle, @mich1972 and @mashthyme for their thoughts.

Jacob

[ajb173]

Thank you so much. Here is a photo of the base. We've had aphids in the past and definitely no sign of those this time. Can't see any other bugs other than the odd cob web wrapping around some leaves that are curled. Are these images ok? 

   

[mich1972]

Good Afternoon @ajb173 I was just looking at your Virburnum photos , thank you for posting a few of them as it helps us to identify what is going on. Now this is just my opinion. It looks like Viburnum odoratissimum species with the large leaves , very common , very beautiful as a hedge. Here in Perth in the Summer months it get extremely hot and dry harsh heat. This species tends to get sunburnt every year. The photos here look to me like sunburn. Sunburn and drying out can cause the leaves to curl up as well.

Also it could be a burn from wind drift from chemical spraying ect.

It could also be a root rot it the plant is dying back from the top downwards. Water logged soil.

So it could be a few different causes.

But to me it looks like sunburn , especially when you prune back a plant and the undergrowth can definitelyburn.

Let's wait and see what @Noelle @mashthyme  thinks when they see them.

I hope this helps and it's not too confusing for you  

[mich1972]

@ajb173 Just looking at these photos of the base, they look ok. I would suggest maybe to push away all of that leaf litter and any mulch that is sitting right up against the trunk of the plant. Make sure that is clear.

[Noelle]

Hi @ajb173 

In my opinion, @mich1972  has hit the nail on the head - it looks like leaf scorch/sunburn. I also agree with the recommendation to move all the leaf litter etc away from the base of the plants, to ensure the trunks don't start rotting. Clear soil also allows air into the soil to the roots to keep them healthy.

[ajb173]

Thanks everyone for taking the time to reply. Really appreciate the advice. I'll get to clearing the base of the trees asap. 

[mashthyme]

hi @ajb173 & @JacobZ 

I agree the larger spots seem to be sunburn from the large pruning.

The leaf in the photo 3rd from the bottom, however, seems a little different. It looks a little like what happens to Camellia's when they're water logged: their pores burst. It's called Oedema. 

The curling of the young leaves could be water stress, or the result of aphid attack when the leaves were at tip stage.