In winter, store the rhizomes in an unheated cellar or garage where they will keep cool but not freeze. Don’t let them dry out completely. Keep the soil in the container barely moist; or if the rhizome is not in soil, wrap it in burlap that can be kept moist.
Hardy water lilies are propagated by planting divisions of the roots, with each section having at least one growing point.
In the wide selection of available varieties, the following pygmies are suitable for most miniature pools.
Nymphaea Nymphaeaceae Pygmy Water Lily
adorata minor—Pint-sized variety of the native pond lily with fragrant, dainty, white three-inch flowers in generous profusion; leaves lined with red beneath. ‘Helen Fowler’ is a fragrant pink-flowered variety.
aurora—An old hybrid, more dwarf than miniature, but suitable for small pools. Changeable flowers open soft yellow, darken to rusty orange in the second stage, then to deep red in the third stage. The small leaves are mottled with wine-red lines.
‘Jo Ann Pring’—True pygmy with three-inch leaves, dusty-pink flowers lighter in the center.
‘Patricia’—One of the few small tropicals with crimson flowers, brown-metal buds. Young plants are borne on the leaves.
tetragona (pygmaea)—Smallest of all, with long-lasting two-inch white flowers with a fragrance like China tea, four-inch soft green leaves. Easy to grow, even in shallow water. The variety alba, or white pygmy, seems the same to me as the variety helvola, an old hybrid usually listed as yellow pygmy, and is even smaller than the species, with brown-blotched leaves and glowing yellow, star-shaped flowers.
‘Royal Purple’—A new red-purple, tropical lily.