Bacterial infection confirmed

A new disease hits viburnums at RHS Garden Wisley

 Last week we had a mystery disease affecting our near-native viburnums. After close inspection from our plant pathologist, Liz, we now have the results back. Here is her diagnosis:
 
"Following examination of the Viburnum sargentii 'Onondago' plants, I noted brown/black angular spots. These spots had yellow halos. Some were following the leaf veins and complete die-back of some leaf tips was noted. After examination under the microscope I noted bacteria oozing from the blackened areas, especially the leaf veins. This is a disease called Viburnum bacterial leaf spot caused by the bacterium Pseudomonas syringae pv. viburni. It is relatively new to the UK, but is widespread throughout Spain and the USA."

Thankfully, this bacterial leaf spot is not systemic so we have not been forced to remove the entire plants. However, I want to take no chances with all this wet weather so have carefully pruned out all the affected shoots and cleared up any leaf debris from below the plants. Hopefully this will halt the spread of the disease.

On a more positive note, this year is the first time our Azara serrata have flowered.

The flowers are said to smell of vanilla but I confess I couldn't detect it! Here are Judi and Sarah having a sniff too (as seen from me up the ladder)...

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