Daphnes have tricky root systems and can go under due to the roots rotting, or getting too dry, or getting rocked by winds, or no apparent reason at all (see Daphne Sudden Death Syndrome, or DSDS). If the roots are gone, so is the plant, and there's nothing you can do. Otherwise, leave it be, protect it from harsh sun and wind, and DON'T water it more in an attempt to revive it -- that'll just swamp the roots.

Hope it pulls through!

Jim

Daphnes are famous for committing daphnecide for no apparent reason. Wonderful plants, easy as can be, then all of a sudden, gone. I have two, so far so good. I adore them and would replace them if they suddenly died. Mine are daphne odorata, which I don't think is hardy in zone 7.

Sorry, it is daphne odora. I got carried away....

Most likely a vascular system problem with nutrient and water flow. Three things come to mind-climatic, artificially induced, and naturalistic invasions due to an organism. Climatic is easy to figure out, usually high stress due to high heat, wind, reflected light, water loss, and over-watering. Artificially meaning a homeowners neglect to provide water, nutrients, clean manicuring techniques, and damage to roots by over-excessive use of preemergents, fertilizers, herbicieds, and fumigants. Naturalistic invasions happen by either a insect ( root weevils, vine weevils, armyworm, grubs and so on), soil-borne bacterium, virus, disease, and molds that slow down the vascular system of the plant accelerated by the other two systematic problems I stated before. My advice, do not spray the plant, look around the root system, do not over-water but make sure the Daphne is easily watered around the whole drip-line of the plant, check out the outer bark for notching, and take a couple of cutting and examine the cambium layers of the cutting, to look for blocked water ways. Check for weevils at night, and grubs doing the day. If no insects appear, checking the root mass for problems whter its a soil problem, or if it is a bacterium/rot.

When I sprayed my Daphne Odra with some kind of furtilizer (the kind to mix with water), her leaves all wilted and thought she is going to die. Except her canes are healthy and have many tiny leaves coming up. I am checking her daily to see how she will recover.