Into this 5th day of temperatures into the mid 90's and oppressive humidity, my thoughts have turned to protecting

our "cold hardy", in-the-ground palms in the dead of winter. I was reading recently, that the fibrous, dark-colored trunk of Trachycarpus is an adaptation to winter cold. I have two outdoor fortunei palms (about 5 feet tall) planted on the south side of the house. They get sun year round. My question is how useful are those white insulating blankets? I have used them (with Christmas lights beneath) to wrap the trunks of the fortunei (leaving leaves exposed), but I was wondering if maybe it was warmer for the plant to have those dark trunks exposed to the sun. Also wonder about isolating blanket and the potential problem of trapping in moisture. These palms went though the winter fine only with some bronzing of older fronds (younger fronds and bud fine). Thanks in advance.