A Grand Species
The Tropicals
Tropical water lilies do everything on a grander scale than the Hardies. They grow wider and taller and in a greater range of color. Their blooming habits are more versatile, half of them blooming in daytime, the rest opening at night. Almost all of the day bloomers and a few night bloomers have fragrance. Many carry their blooms aloft, well above the surface of the water, and long, strong stems make most of them excellent for cutting. As a rule of thumb, these aquatic flowers are considered annual plants in cold climates. They certainly will not winter outdoors and they require continued growth to live, which requires a heated water tank with grow lights right above the water surface. With the costs of running water heaters and grow lights, you are breaking even at best.
There are more species of Tropicals than of Hardies as they hybridize more readily resulting in a tremendous number of varieties (incidentally, the terms hybrid and variety are used interchangeably). The foliage of most Tropicals is spreading and luxurious. Many of the species and varieties are toothed and crimped or fluted at the edge. Most of the Tropicals require more pool or pond space, half to twice as much as the Hardies. Here is some advice about how to care for and maintain both types.
Tropicals Versus Hardies
Tropicals are not as versatile as the Hardies, however, when it comes to growing, for they must have comparatively shallow water at the start. They do well in water lily pools, large and small. They thrive in ponds when planted around the shallow edges or propped up in the deep water to a level from which blooms can break the surface. Tropical pond lilies are very greedy feeders. You have to feed them well if you want them to attain the large, pond enhancing sizes. If you choose not to feed them, I would suggest you not bother growing them as you will be disappointed. Day and night blooming Tropical water lilies should be planted in a 2-3 gallon pot. Fill the pot half full with a rich heavy garden soil and add 2-4 aquatic fertilizer tablets. Potting soil, compost, vermiculite, or perlite should not be used, as they float out and foul the water. Continue to fill the pot with soil to about 2 inches from the top.
As with the Hardies, I include several species and varieties which may seem identical. That is intentional, for I want to present a complete range of colors and shapes, even if overlapping is required.
Several species and varieties of day-blooming Tropical water lilies have an interesting characteristic that few other flowers have. They are viviparous, that is, they bear their young alive, in the form of miniature plants and blooms which sprout from an umbilicus at the center of mature leaves.
Here are a few examples of day-blooming Tropical lilies:
• African Gold
• American Beauty (N. ampla)
• Bob Trickett (N. Burttii) -- The plant is still an enigma. Difficult to propagate and grow, but hybrids reproduce readily from tubers. The plant proved to be a new species when studied at the botanical gardens and was named for the discoverer.
• Cleveland -- rose-pink blossoms.
Maintenance
As long as the water temperatures are 72F or 20C, Tropical water lilies will continue to bloom. As soon as the water temperatures drop below these temperatures these aquatic plants stop blooming. So, Tropicals will bloom later into the fall than the Hardy types (Hardies start going dormant when the sunlight decreases). As the weather cools, Tropical pond lilies are finished.
Plant your Tropical water lilies in the same way as the Hardy pond lilies, ensuring you have at least a half bushel basket sized pot for all but the dwarf varieties. Remember, this is a large plant and wants both root space and water surface/sunshine space. Tropical lilies want full, hot sun for best performance.
When to Put Outdoors
Do not plant your Tropical water lily until the water temperatures have reached the 72F / 20C mark. If you plant too early and the water is too cold, the root will likely go dormant and sit idle. You will lose flowers and possibly the root. Use a water thermometer to ensure you do not plant too soon.