Tropical Water Lily Culture in Temperate Climates

Appeal: Although they require more specific care than hardy water lilies, the tropical varieties of Nymphaea can reward the grower with exotic features that are not available in the hardy varieties. The most obvious difference is the range of flower colours: in addition to shades of red, pink, white, and yellow; many tropical varieties produce flowers in blue, purple and even green hues. It is also common for the flowers of tropical lilies to be extremely fragrant, a feature assisted by the tropicals' habit of elevating their flowers up to 12" or more above the water surface. Blooming is usually more profuse in tropical lilies compared to the hardies; it is not unusual for a single plant to have multiple flowers open simultaneously. Some varieties are sought after due to their colourful foliage, often heavily mottled in shades of purple or maroon. There are also many night-blooming varieties of tropical lilies, a very pleasing sight at dusk and particularly appealing at nightfall in an illuminated pond.

Care: Place tropical lilies outdoors after the water temperature has warmed up to 18 Celsius (65 F) or more; usually by late June in the Pacific northwest. Tropicals destined for an in-ground pond can be temporarily placed in a large ceramic bowl or plastic (resin) tub situated in a sunny sheltered area outdoors if the pond is slow to reach this temperature. You can also give your tropicals an early start by adding a submersible aquarium heater to the outdoor lily tub; or by placing the planted tubers in a well-lit aquarium indoors. Initially, the lily tuber should be planted in a small pot, usually only 3" to 4" in diameter; using a moistened heavy loam. Once the plant is well-established and roots begin appearing from the drainage holes of the pot, the lily is ready for transplanting into a larger pot. Use a pot approximately 8" in diameter but not too deep, a #2 short nursery pot is ideal. Tropical water lilies are heavy feeders, adding a scoop of bonemeal around the roots helps promote healthy growth. You should also add water lily fertilizer tablets, approximately 3 tablets for an 8" pot. After planting, the pots should be placed in shallow water with only about 6 to 12 inches of water above the crown of the lily tuber. Placing a tropical lily in deep water, particularly in the cool Pacific northwest, will be detrimental to the growth of the plant.

Winter Prep.: Tropicals will bloom late into the fall but should be moved indoors by early November in the Pacific northwest, earlier in the colder parts of Canada. Winter preparation consists of a thorough washing to remove the soil, followed by the trimming away of all the leaves and roots from the tuber. It is prudent to briefly soak the tuber in a fungicide solution prior to storage. The tuber can then be buried in a clean container filled with damp sand and stored away for the winter at a temperature of approximately 10 to15 Celsius ( 50 - 60 F.)

Jack Wootton

Information provided by Hawaiian Botanicals Inc., copyright 2005