I've got plants in heavy pots on the patio. If the weather is going to be really cold or snow/ice/heavy rain, I wrap bubble wrap around the pots and tie with string. Then clip the upper edges together to form a collar (clothes pegs or bulldog clips). This shields the plants well but leaves top open for water.

If you don't have any bubble wrap, use refuse bags/bin liners. Poke some holes in so the plants can breathe, then place over top of plants and tie around pots. This method is good for a few days only as lack of light affects the plants.

This worked fine for my blueberry bushes. Got rid of them earlier this year as they were 10+ years old and fruit yield wasn't great. They did survive snow, ice, wind, rain. All the usual weather we get in the UK!