Question: I have a large, mature rosemary bush which got through the winter fine, but has suddenly lost several large stems. The foliage is still on the stems but the whole stem is completely brown, as if it got burnt, and is obviously dead. Can you tell me what is wrong as I am worried I will lose the whole plant at this rate?
© RHS/Leigh Hunt
Answer: If cold damage was involved I would expect the whole plant to have gone brown, so I think you must assume either disease below the affected part or the rather common natural die-back of what can be a short-lived shrub.
I am afraid you can do no more than cut out dead bits and trust the plant recovers. However I feel that you may well have to replace this plant, ideally after removing roots and changing the soil. Happily, new plants are inexpensive and quick-growing.
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