What to do with pond plants?

Next to my large barrel, I have a smaller one filled with large pebbles, water, and plants. The plants are red Lobelia and Houttuynia submerged in perforated pots,a sprig of weeping willow which has rooted, and lots of Kniphofia just shoved in. All are doing well, but will they survive being frozen or should I drain the water out?

 

My pond got frozen solid last winter (first winter!) and the plants survived. Trouble is, I can;t quite remember what they are ... ! One is a water buttercup. I had Iris but they didn't make it.

 

Liz, you could try bubble wrap I use it here and there for winter protection. Wrap some around your tubs and if the weather gets really really chilly put some over the top as well.

 

I'm a big fan of bubble wrap Liz

 

Thanks both......I like bubblewrap too... I like the large bubbles for garden use and will try that on my barrels, but I like the small bubble type for popping. Very satisfying.