I seldom plant daphnes. They too often die. Perhaps yours has root rot.

are mentioned by this site.

Here is a link that might be useful: Index, An Online Guide to Plant Disease Control, Oregon State University

Do not panic - it is entirely normal :-) Selections of x transatlantica and x burkwoodii are considered semi-evergreen. It is very common for them to lose a good percentage of their foliage in even a "normal" winter. From the Great Plant Picks website: "In cold winters it is completely deciduous; in average winters it retains about half its leaves." It should begin to bud up and releaf in spring and by the time blooming season arrives, it will be full and lush once again. Even Daphne odora is prone to some leaf drop in winter.

Good drainage is critical to growing any daphne well. As long as drainage is sharp, you shouldn't have much else to worry about.

Thank you, gardengal. I would hate losing this bush.
When i planted it i read that Summer Ice will not commit suicide as other daphnes.
Bboy, thanks for a link. I will save it in favorites. I have checked my bush, it does not have water-soaked lesions. Hope this is not a root rot.
Place where it grows has good dranage. Will wait for spring.

You're correct, brier - SDD (Sudden Daphne Death) is not nearly as prevelant with some of the hybrids as it is with species like Daphne odora or cneorum. I've had my share of fatalities with those but never with xburkwoodii or xtransatlatica, which are quite a bit more resistant to this issue. I had a very large, mature and well established 'Carol Mackie' in my former garden that went through similar seasonal changes in leaf drop. It looked like it was on death's door each winter :-) But as soon as the temperatures started to warm up, it would rapidly develop new leaf buds and by the time it flowered in mid May or early June, it was once again in full leaf. I intend to acquire another (or a 'Summer Ice') for my new garden, as it couldn't be easily moved nor would it have appreciated that disturbance. I did manage to dig and relocate a younger D. xhoutteana to my new garden and it's thriving, despite our recent cold weather.

Even 'Brigg's Moonlight', which had a terrible reputation for nearly instant decline once planted, has become a much more reliable performer in the garden, although its heavy variegation makes it a slower and smaller plant. And not a very heavy bloomer, either.

I've been lucky with D. odora, cneorum and 'Summer Ice'. My odora by the front door is between ten and fifteen years old. Survived the stoop and walkway being removed and a new one poured. Thought for sure it was a goner since the guys stepped on it.

My D. odora has extremely sharp drainage and does great, the Summer Ice not as good drainage but is on a slope and does well. My more exposed large plant has lost most of its leaves, whereas the small one near my concrete E-facing porch is untouched, so exposure seems to play a part. D. cneorum and Brigg's Moonlight both bit the dust for me. I have D. collina x arbuscula Lawrence Crocker with a purple flower that is small but does well, and D. tangutica which is a 2-3' bush now; both seem to do very well.

Slopes have no horticulturally useful effect on internal drainage. That's why wet clay banks have water seeping out of them for months, if not all the time. The soil behind the slope is still wet clay, slope or no.

It's the texture of the soil within that's critical, not the surface contours.

Then I would suppose my soil drains well.:-) In San Diego I had raised beds with high sides supported by large stones, and I could water the entire bed by putting a hose at the high end and the water would run down the whole bed, but here if I put a hose at the high end the water all runs straight down, probably aided by vole and mole tunnels reaching to China.;0

But beds that are flat kill more plants than beds that slope in my experience.