Yellow leaves on Laurels
Approximately two years ago I had the well established Laurels in my back garden trimmed back to a height of about four metres and since then I have two of them died off and have removed them. In fact, having them removed seems to have sped up everything and I have another two that are already dead or on their last legs.
This year's growth from the stumps of those I removed are starting to turn yellow and there are a lot of the smaller branches that are brittle and break off very easily; however, if I try to prune these smaller branches, it seems to aggravate the yellowing.
I have had a look at your site but the causes shown seem not to agree with what's happening. The soil (or lack of) is usually dry and I can see no signs of an insect infestation, so I am looking for any suggestion anyone may have before they all die.
A very likely candidate for causality is disease - fungal, viral, or bacterial - in the soil. The only way you can tell for sure is to get a professional analysis done. You could hire a certified arborist. You could also call the nearest university that has a botany department, to ask about bringing in some soil/leaf/branch samples. You could also contact the master gardener program in your area; you can find the number by requesting it from a botanical garden near you.