The seasons are changing, and even though it might not feel like it, winter is just around the corner. While you are preparing your pond for the cold, it is important not to forget about a vital part of your little ecosystem. Plants! Even though they can be easy to forget about, they need as much end-of-the-season TLC as the rest of your pond.
Keep in mind that this advice is for perennial or hardy plants only. Tropical or annual plants, such as Taros, Cannas and Water Hyacinths and Water Lettuce need to be taken out of the pond and kept indoors until next spring (or until it gets to be 70 degrees outside)
The first thing to keep in mind is as it gets colder is to stop "feeding" or fertilizing your plants mid-September. Similar to koi fish, the plant food will keep your plants active when the plants would naturally go dormant, which is an essential part of the life cycle of your plants.
After that, it will be essential to remove all dead plant matter and trim down the growing parts of the perennial plants to about 5-3 inches above their soil line. This will make sure that the plant can come back next year. If the plant is in a planter, you'll want to move it deeper into the pond once it starts to hit freezing temperatures at night. If it is not in a pot, it is okay to leave it where it is and not disturb the roots.
The last thing is to make sure that your plants will get oxygen over the winter. A de-icer will do the trick pretty, and if you have fish, they need this too!
This should allow your plants to go dormant over the winter without dying and come back much stronger, healthier and bushier next spring!