I have extreme differences in temp. living in Manteca, ca. 95336 zone 9b. I have two Dragon Trees (Drago) from the Canary Islands and they are approximately 15 years old standing between 4' and 5'. They were damaged by the frost and I did cover them with burlap and tarps as well as wrapped the trunks. I just moved here in summer time and the temps in summer are triple digit, yet winter time lows can be in the 20's. I have a large potted bottle palm that is in doors but it is too big and fronds are hitting the ceiling. I want to put outside under my covered patio with a space heater and heat light. Any suggestions for protecting palms from frost damage is greatly appreciated. Thank you. By the way my garden consists of 2 Aloe Bainseii's (both severly damaged and cut down to half their size) 2 Dragon trees (one I dug out of ground and potted it so I can move indoors if severe cold persists) 2 Sago Palms no damage whatsoever. 2 King Palms no damage yet, 1 Bismarckia Nobilis no damage yet, and 2 Butia Palms (Pindo Palm) no damage yet. Any ideas or suggestions greatly appreciated. Thanks again.