Pond Plants in Winter

The answer to your question lies in the answer to more detailed questions about you pond and your local climate zone and what zone your plants are from . You see if for example you are pushing zone boundries like I do you need to get a little creative.  I am in a zone 5 but over winter plants that are zone 6 to 7 as well as all the very hardy zone 1to 5 plants. I do this by changing the mico climate in winter with a temp. greenhouse.  Now back to yours, is yours deep enough to keep the plants roots and tubers from freezing . Depending on where you live the ice can get a foot deep. What zone are you in and what zone are your plants? Any and all tropicals have to come out . Most  (hardy) plants will be just fine as long as you can keep them from freezing(ice zone).To do this just sink them to the deepest point of the pond or do like I do and keep it from freezing altogether. Now a few tips on sinking you plants. First and formost cut back fleshy plants   but do not cut back long stemplants like Reeds and Rushes as they breath though the stems . But ratherclean away excess folage. Secondly attach a rope to each of them so bringing them up in the spring is easier , in the spring is when you cut back you rushes and like to about 2 inches above water level. Your water lillies will be fine if root tubers are 2 feet below water level so as not to freeze. I hope this answered some of your questions and strired up some more as quest to improve my garden is what has driven me.