Q: We came back to our home this fall to see our 25-year-old Leyland Cypress & 10-year-old Sky Pencil holly dying. Any idea as to cause? Any hope?
A: They both look like they were damaged by dry weather. Leyland cypress in particular will quickly go from green to brown if the roots dry out for more than a day or two. ‘Sky Pencil’ holly should be drought tolerant like its holly kin but I recently saw one comparable to yours that was completely brown.
That said, last week I drove past a line of big Leyland cypress trees that had many brown limbs ten years ago. I was confident the canker disease would spread and they would die in a couple of years.
But I noted as I passed recently that the brown limbs are no longer present and the Leyland cypress trees are uniformly healthy and green. So I am loath to predict what will happen with yours. But it is possible they will survive this setback and get better in the future.