Garden Q&A: Can I stop viburnum shrub disease from spreading?

Whether you're a gardening beginner or expert, Irish Examiner columnist Peter Dowdall has the answer to your questions

Viburnum in bloom. File picture

QUESTION

In the past year, some Viburnum tinus shrubbery has begun to die in a corner of my garden. The disease seems to be spreading and I wonder if you can explain the cause. The shrubs were planted the best part of 20 years ago. I am anxious that it may spread further as I would not like to lose a neighbouring magnolia tree. I hope you may be able to give an educated guess.

ANSWER

It looks to me like your viburnum has been infected with phytophthora. This is a fungal infection which is spread through the soil and our damp and warm climate creates the ideal conditions for its spread. 

Viburnum in bloom.

Unfortunately, there is little or nothing that you can do to save your viburnum. The only advice that I can give you is to remove all the infected growth and much of the healthy growth and feed the plant with good organic, seaweed-based plant food. 

Clean and disinfect tools

To the best of my knowledge, magnolia is not a host plant for this disease but avoid moving infected soil around the garden and prevent the spread of the disease to other areas of the garden by ensuring you clean and disinfect spades, pruners and anything else that you use on the infected plant.

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