I don't think that's from sun. Seems likely due to the cold.
As I mentioned above, They do fine in the full sun down here where the sunlight is harsher than your area.
While they tolerate a good deal of shade... I've noticed that they don't produce blooms as quickly (at my house) as when they get better light.
As far as when to remove the enclosure?
What kind of weather do you usually get from here on out?
Spring at my house... But last year, we had a late freeze in March... Killed all the flowers on all the fruit trees... Apparently, the peach growers lost 90% of their crop...
