Hardy lilies open in the early morning and close in the late afternoon. Tropical lilies come in day-blooming varieties and night-blooming varieties. Hardy lilies are available in red to almost black, pink, white, yellow, orange, or peach shades. Tropicals come in a wider range of colors, including blues and purples. In addition, hardy lily leaves tend to have "smooth," round edges, while tropical lily leaves have "serated" edges.
Winterizing Hardy Water Lilies:
Please note that this technique only works with "hardy" water lilies. In other words, they must be plants that normally spend winters in dormancy. Tropical water lilies are typically treated as annuals.
Once outside temperatures have dropped, find container that is roomy enough to accommodate the pot your water lily is planted in. Take the plant from your outdoor garden (pot and all) and place it in the winter storage bucket. Be sure to remove all dead and dying foliage. Move it to the place it will spend the winter, then fill the container with water, covering the surface of the plant's soil by 2-6 inches.
Continually check the water level occasionally to make sure it's still covering the soil surface by a few inches throughout the winter season. Once spring arrives, you can then return the lily to its spring/summer home.