Of all the water garden plants to choose from the Water lily is the most popular. They help to shade the pond, protect the fish from the sun and predators and the blooms are amazing. Water lilies are divided into two main types, Hardy and Tropical and their differences are more than skin deep.
The biggest difference is how they react to cold weather. In the northern climates, a Hardy Lily can with stand the freeze if left in the pond while the Tropical is removed and over wintered. Lucky for us, in the south we do not have to worry about removing our Lilies from our ponds and we can enjoy both types nearly all year round. Both types may go dormant, but will start to sprout again come spring.
Physically the differences are easy to spot. Although both Hardy & Tropical Water lilies are available in sizes ranging from dwarf to large, the Tropical Lily pads tend to be larger than the Hardy. The leaves of the Tropical Lily are thin, scalloped or irregular and can be green, maroon or mottled, and the Hardy has a round thick waxy leaf that is usually solid green or slightly mottled.
Both types have blooms in a range of colors with the Tropicals in white, yellow, pink, purple, blue and red and the Hardies in white, yellow, pink and changeable autumn shades. The difference is the Tropical flower will bloom high above the water in intense color with wonderful aromas while the Hardy bloom will float on the surface of the water or just above in a pastel shade and is not fragrant. You will also find that a Tropical Lily will have more blooms per plant than a Hardy Lily. For the night owl there are night blooming Tropical lilies. You can distinguish them from the Day bloomers by their toothy edged pads and the fact that the bloom only opens when the sun goes down and stays open until mid morning.
Even the roots of these beautiful plants are different. The Hardy Lily stems from a horizontal rhizome or tuber and the Tropical tuber is round. Tropicals can also be viviparous sprouting baby lilies from the nub in the center of the leaf. When transplanting your Lilies, no matter what type, you want to plant in a heavy clay loam soil. Commercial aquatic plant mix, top soil, clay and even non-scented non-clumping kitty litter are good choices for potting. Water lilies are heavy eaters so be sure to fertilize your Tropical and Hardy Lilies every month from spring through summer to ensure plenty of blooms. Personally, I prefer to fill my pond with both Tropical & Hardy, day and night blooming Water lilies, the more the merrier.