Back to Home   Back to Info Sheets	Overwintering Your Aquatic Plants. Hardy Water Lilies:       Hardy water lilies and lotus will overwinter if their roots do not freeze solid.  Foliage will die back mid to late fall but roots will remain alive.  Steps to overwinter lilies should be taken at this time. Methods: A.    Move containers to the deepest area of the pond.  It is recommended that your pond be at least 2.5 to 3 feet deep in one area if this method is chosen.  Colder zones in Canada should increase this depth.  You may cover the pond with boards or framed plastic to provide extra insulation. Do not make airtight.  Return containers to original positions in spring. B.    Use this method if your pond is shallow and will likely freeze solid.  Remove the old leaves from the lily and bring planted containers indoors to cold storage, approximately 40 oF or 5 oC, for the winter.  Keep containers moist and dark at all times.  More lilies are lost from drying out than from freezing.  Return plants to the pond after the ice has melted the following spring.  Note:         Northern areas of Canada should bring plants indoors or use a pond heater just to be safe. Hardy Shallow Water Plants      Some hardy shallow water plants can tolerate being frozen solid while others need their roots or tubers to remain in the water.  Iris, Sweet Flag, Cattail, Horsetail, Marsh Marigold, Variegated Manna-Grass and Water Forget-Me-Not may be left in shallow water where they will likely freeze.  Most other varieties should be moved to deep water or brought indoors to cold storage.  (See method B above.)  Return all plants to growing shelves as soon as the ice has melted in the spring. Note:     Do not remove dead leaf stocks from emergents such as cattail until spring.  This will allow the root system to "breath" during the winter.
© Murray's Garden and Horticultural Services Last updated: March 1 2008