In "Daphnes: A Practical Guide for Gardeners" (Timber Press 2006) the author, Robin White says "It is common to hear or read of apparently healthy, well-established daphnes suddenly collapsing for no apparent reason; in the United States this has been named 'daphne sudden death syndrome'."
Here is a picture of my Daphne x susannae 'Cheriton' as it was in early July last year when it looked happy, in good condition and flowered on and off for some months.
... and here it is now:-
Robin goes on to say that this disease is common in small evergreen daphnes that have a bushy habit extending to soil level with dead plant material gathering at the base of the plant. He also says, and this is what alerted me to the problem a few days ago, "........ or an area of leaves on a healthy green plant turning olive green and then brown"
