It's not clear from the picture whether the white blobs are outgrowths from the stems, or something that's attached themselves. Have you tried picking them off, and if so, what do you find underneath? My guess would be scale insects, but I'm sure someone better-informed will be along soon.
Yup scale insects, mine were infested a couple of years ago. Clean them off the stems as best you can as they zap the strength of the plant. Good luck it’s tedious but mine came back ok the following year.
Marne la vallée, basically just outside Paris 🇫🇷, but definitely Scottish at heart.
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