In very simplistic terms, the stomata moisture, like water in a household water pipe, expands when frozen and if this is heated up by sunshine which acts through the frost as a magnifying lens is the 'bit' that does most damage. +++++++++++++++ Hi Gang, Iain described how to protect plants that might have been exposed to mild frots, plants that might even have some frozen water in the leaves. I'm forever amazed anew by plants and their clever ways. how they know when to bloom, or when to become dormant, or how they are such amazing chemical factories. I've heard about the frost and sunlight problem before, but never really understood how it works. Can anyone explain what goes on when sunlight damages frosted leaves? Cordially, Joe Conroe TX P.S. One more Crinum is in bloom this fall; flowers can just pop up when you don't look for a day or two. This unknown plants is a foundling that resembles (but is not) 'River Forks'. In turn, 'River Forks' is a beautiful plant; I sometimes wonder if it is C. amoenum. LINK: Found Crinum, 'River Forks' http://marcellescrinums.com/html/crinum-found/… LINK: C. amoenum (Plant Delights Catalog) http://plantdelights.com/Catalog/Current/…