Serenoa repens MSI
10F is probably the lowest this palm can tolerate without leaf damage. Some say the bluer/silver leaf forms are a bit more cold hardy. Florida results for this palm may be different than the lower humidity environments in California or the Mediterranean. It may be a better choice for cold 'humid' climates than cold dry climates, as the latter do not promote fast growth. In low humidity climates where there is no alternative hot days, this palm will often sulk and eventually die. So its cold hardiness along the east coast may be more impressive than along the west coast of the US.