I sometimes get annoyed by persons who say in affect go look somewhere else for your answers. Having said that I admit that sometimes I do it myself. I suggest you go to Gardening in Texas - GardenWeb and repost your query.

I have read of some experiments that use electricity to prevent frost damage using electricity - look up electroculture or electro-horticulture. Basically, applying a DC electric field to the soil will be the way to test it out. Let me know if you decide to give it a try!

Hi
Albert probably has the best respose as there are soooo many variables I live in s. florida so what works for me may not work for you What is your general lowest temps and for how long?? Bottle brush survives temps into the 20s easily but I'd bet it couldn't handle it all day long or repeatedly
My most extreme is for a Vanda orchid bed I use frost cloth held up by PVC pipe ,heated with a lightless infrared lamp with thermostat.. Always keep it above 50 year around. it's used lesss than two weeks out of the year and then only for hours at a time.. My biggest problem is overheating after the front has passed
For general frost protection i wouldn't recommend any type of plastic . Used bed sheets with or without christmas lights work well and are easy to store . very light weight and cheap . They do make reactive "frostcloth" that produces heat if you need to go that far ??? gary