Do you know the species of water garden plants which can survive in winter?
you have no idea, or just interested in plants, come to the lesson on gardening--overwintering water garden plants.
TROPICAL MARGINALS:
As the term “tropical” implies, these plantscannot survive freezing. They too can be treated like annuals and replacedevery spring or you can try to overwinter them indoors. If this is your choice,remove them prior to a killing frost. Umbrella Palm, Papyrus, and ParrotFeather can be grown as houseplants. Simply position them in a sunny window andkeep moist. They don’t need to be standing in water. When the pond watertemperature reaches 21°C (70°F) in spring they can be returned to theirshallow position in the water garden.
For Canna and Taro, remove the plants from the pond and letthem dry out naturally. When the foliage has died back, cut it off just abovethe bulb or rhizome. You can keep it in its original pot but don’t letthe soil dry out. Or you can remove the bulb/rhizome, rinse off any soil thatclings to it, and store it in slightly damp peat moss or sand. Or, thirdly,place the pot(s) in a tub of water in a cool basement that’s 4-13°C(40-55°F).
TROPICAL WATER LILIES:
Like the tropical marginals, tropical Water Lilies can bereplaced every year or overwintered indoors. In the case of the latter, thereare 2 methods. The first is to keep them actively growing by placing them inwarm water with bright light and warmth. The hard part is maintaining a minimumwater temperature of 21°C (70°F). Often this is only possible if youhave a greenhouse or sunroom. If your Lily survives it can be returned to thepond when the water temperature reaches 21°C (70°F). This is usually inearly June.
The other way to overwinter a tropical Lily is to let thetuber go dormant. Leave the plant in the pond until after a killing frost. Thecold water will induce the formation of a small, black, grape-size tuber. Olderspecimens may have already produced several. Gently rinse all the soil from thetubers and float them in lukewarm water for a day. Viable tubers will sink andspoiled ones will float. Discard the spoiled ones. Place the viable tubers indamp peat moss or sand. Store in a cool basement. Check them from time to timeto make sure the peat moss or sand doesn’t dry out completely.
In early May check to see if the tubers have any sprouts. Ifthere aren’t, place the tubers in distilled water in a sunny window tobreak dormancy. When roots are 1-2.5 cm (1/2” -1”) long pot them 6mm (1/4”) deep in heavy soil and submerge the pot(s) in 7 cm (3”)of water. Maintain a minimum water temperature indoors of 21°C (70°F).When leaves emerge and the pond is at least 21°C (70°F) they can besafely returned outdoors to the water garden.
HARDY MARGINALS & BOG PLANTS:
This group of aquatics can be left in the pond over thewinter if it’s at least 50 cm (18”) deep. After frost has killedthe foliage, remove the leaves and move the plants to the deepest part of thepond. Don’t cut back the stems of Cattails, Rushes, Reeds, or otherplants with hollow stems. If these stems fill up with water the crown of theplant can rot. For shallow pools or streams, plants would need to come indoorsand be placed in a tub of water in a cool place like the basement. Thetemperature should be around 4-13°C (40-55°F).
HARDY WATER LILIES & LOTUS:
As long as the roots and crown don’t freeze solid,hardy Water Lilies and Lotus can also be left in ponds if they can be moved toa depth of at least 80-90 cm (2 1/2 -3’). In late fall, remove allfoliage so leaves don’t decompose in the water. If the pond is shallowand likely to freeze, remove old leaves, bring plants indoors, place in a tubof water, and store in a cool, dark place. Return plants to their proper depthafter the ice has melted the following spring. Or remove the Lily from the pot,cut off all foliage, and rinse all the soil off the rhizome. Store the rhizomein damp peat moss or sand in a plastic bag at a temperature of 4-13°C(40-55°F). Keep the peat moss or sand moist all winter. If the storagemedium is too wet, the rhizome will rot. If too dry, the rhizome dehydrates anddies. Repot the tubers in spring and return to the water garden after the icemelts.
