FWIW, I have 7 landscape yews along my driveway, approx 50 yo. Last fall two on the end began browning so I began researching. Normal lifespan for an in ground yew is 400 yrs, so the problem is not age. They are highly resistant to pests and disease. About the only thing that will kill them is TOO MUCH WATER which can also lead to a contagous root fungus. The two died over winter and I had them removed this spring. The next two are now browning. I suspect l will lose them all, one after another.
The planting conditions have not changed over 50 yrs except for normal soil compaction. Check your substrate and make sure it is STILL draining well.
The planting conditions have not changed over 50 yrs except for normal soil compaction. Check your substrate and make sure it is STILL draining well.