Overwintering Plants
Overwintering Plants
As majority of the water plants are of tropical or subtropical origin, special care should
be taken to ensure they survive harsh frost conditions. All plants will succumb to frost
when they are covered with ice. Some plants such as winter hardy lilies, winter hardy
marginals and winter hardy submerged plants can be wintered in the pond itself so long
as they are kept in the ice free area of the pond
Wintering Water Lilies
Tropical Water Lilies:
Most of the water gardening hobbyists from Zone 8 or below (ac-
cording to the 'Plant Hardiness Map' designed by Unites States Department of Agriculture)
treat tropical water lilies as annuals and replace with the new plants when the new growing
season approaches. However, they can be left in the pond in Zone 10, as these regions are
free of frost during winter. In colder regions (Zone 9 and below), remove them from the pond
and place them in a green house pond in full sun before the onset of severe frost. Feeding
should be avoided, as growth is minimal. It can be transferred back to pond once the outside
temperature reaches and stabilises at 21
o
C. This practice is only possible for those who
have such green house ponds. Alternatively, we can salvage tubers (walnut like growths)
developed at the base of growing points. Remove the potted plant after the second frost as
this practice the soft tuber to become hard. Wash the rhizome with tubers and air-dry them
for 2 days. Separate the tubers from the rootstock and wash again before storing them in
damp soil or in jars of distilled water at about a temperature of 10-12
o
C until the advent of
next growing season. The tuber formation is a characteristic feature of tropical lilies but
the number of tubers varies from species to species. Follow the same potting technique as
that of tropical ones.
Winter Hardies: This group of water lilies can be treated as perennials as they tide
over winter in the pond through dormancy. They can flourish at any latitude in United
States; maybe even in Alaska. Winter hardy lilies will overwinter successfully in USDA
Zones 3-10 provided that their rootstock are protected from ice. Push the containers
in to the deepest part of the pond where they can undergo dormancy. If the pond is
shallow, cover them with a plastic tent to prevent the water in deeper portion from
freezing. If all above measures fail, remove them from the pond, trim off leaves and
excess roots. Place them in sphagnum moss and store in around the house where they
could be protected from being frozen. In this way, the rootstock would stay viable for
replanting next year.
Marginals can be hardy, semi-hardy or tropical. Confirm first, which are hardy or semi-
hardy marginals in your Zone. Hardy marginals can be left at the same position in your
pond. Trim back to an inch or two above the water level to keep the plant free of dry
foliage. The presence of dry leaves may help the harmful insects to overwinter. Semi-hardy
ones should be moved in to the deepest part of the pond. Pruning is not recommended
for the semi-hardy marginals. However, dead and rotten leaves must be removed
Wintering Marginals
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