Blueberry and Strawberry

[Corzhens]

Do you mean Fahrenheit Corzhens?
Here in the UK we commonly get temperatures below 5C. and find strawberries plent hardy enough for that.
Indeed, I cannot think of a year where they HAVEN'T had temps below 5C.
Below 0C we can get blackeye on proto-strawberries, but it has to catch the plants at just the right stage of development or they're OK.

That is centigrade, 5 degrees that can ruin the strawberries. But you know the news, it sometimes bungle with the numbers. However, when I went to the strawberry farm some years back, the farmer said that when the temperature drops lower than 10 degrees centigrade, it has a bad effect on the strawberries. The morning dew is frozen and that's what ruins the strawberries.