Answer: Unfortunately, based on the information in your question it is impossible to attempt a diagnosis of what may be wrong with your yews. Some typical possible reasons would be root damage or disturbance, deicing salt runoff, a change in drainage patterns making the soil overly wet, or an accidental herbicide overspray. There are also some pests and diseases that could cause yellowing. Finally, the extended periods of dry weather recently could also contribute to their decline. I would suggest you contact your county extension for help in determining the cause of the browning and what to do to help the shrubs. I'm sorry I can't be more specific.
Q&A Library Searching Tips