When I have had plants that I just can't get inside during a hard freeze because of their size I have use bed sheets. To keep them in place I use binder clips to gather the sheet below the foliage so it wont blow off. If the plant limbs can take the pressure from the clip I just clip the sheet to the lowest branches or limbs. I would use clothes pins but have not seen any of them around for years.
another use for those binder clips, thank you
live in south chandler, az. i have some bougainvilleas that i wish would go away, those boogers have thorns.