Garden Q&A: Why does my hedge have brown patches?

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

My Griselinia littoralis hedge has patches of brown and some plants in the hedge have gone totally brown; what can I do?

ANSWER

I am seeing so much of this problem this year; it seems to be everywhere—and unfortunately, there's no real good news nor is there an easy solution. 

This type of dieback on a hedge is normally caused by some type of root rot which is normally, if not always, caused by a fungal infection — perhaps phytophthora or maybe some other pathogen. 

These infections thrive in poorly drained and compacted soils. 

Last winter was particularly wet over a very long period and even well-drained soils were struggling with the sheer volume of rainfall. 

When the roots of your Griselinia littoralis were sitting in saturated soil during the winter months, unfortunately, this infection bloomed and infected the root system of the griselinia.

The bad news is that it will spread from plant to plant. 

If the problem is localised then perhaps you could simply remove a few plants. However, if it is widespread, I would suggest removing the entire hedge and replacing it with something more suitable and perhaps looking at a mixed-species hedge.

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