I had quite a few Otto Luyken laurels die on me over the years. They were planted at various points around the perimeter of the house as part of foundation plantings. The plants would one day have lush dark green shiny foliage and within a few days begin exhibiting dull flat green colored foliage that gradually worsened over time. The plants would eventually die out completely.

What I found was the issue with mine was that since they are members of the cherry family, they can be attacked by borers. If you look at the base of the trunks near where they exit the ground, you could tell that something was chewing up the inner portion of the structure. Some times I could split the trunks open and actually find the grubs of the borers actively at work inside the main trunks. Don't know if this is what is happening to yours by your description or not, but it could be a possibility.

No one could ever offer a suggestion as to how to treat the issue, so the plants were removed and replaced with other evergreen plants as the ones died. Curious thing is that there are still several laurels around the house that have never been touched by the borers and I can't for the life of me find out why.

One other thing is that I have seen the same thing happening to other Otto Luyken laurels in other yards in my neighborhood.

If your problem is borers, and it's pretty likely, the only thing you can do is preventative. First, stress makes borers more likely. The drought is probably not helping your situation. There are borer sprays that contain permethrin. Because the borer moth lays its eggs near the bottom of the trunk or on the trunk itself, spray starting around Aug 1 at two week intervals through Sept. This kills the larvae as they hatch. Once a plant gets significant borer damage, it's pretty much history, although it may take the plant awhile to die. I've found that once the plants mature (at least w/ carolina cherry laurel), they are also less susceptible to borers.

Any alternatives to Otto luyken suggested? I am having the same problem.