While both are iconic aquatic plants, water lilies and lotuses belong to entirely different botanical families, which is the most fundamental difference. Water lilies are members of the Nymphaeaceae family. Lotuses, on the other hand, belong to the Nelumbonaceae family. This distinction places them in separate evolutionary branches. Interestingly, the lotus is more closely related to the sycamore tree and the protea flower than it is to the water lily. This taxonomic separation is the root cause of the many physical and growth habit differences observed by gardeners.
The appearance of the flowers and leaves provides the easiest way for a gardener to tell them apart. Water lily flowers and leaves float directly on the water's surface. Their blooms have a prominent central cluster of stamens and petals that radiate outwards, but the entire flower rests on the water. Their leaves are typically notched (V-shaped) and have a slit.
Lotus flowers and leaves are held high above the water on sturdy, upright stems. The iconic lotus flower has a distinct, conical seed pod at its center and its petals are more layered. Lotus leaves are circular, complete, and perfectly symmetrical, with a water-repellent, waxy surface that causes water to bead up and roll off. They do not have a slit.
Their growth patterns and root structures differ significantly, which is crucial for cultivation. Water lilies grow from a submerged rhizome that spreads horizontally, often in a pot. They are generally divided into two categories: hardy (surviving winter dormancy) and tropical (needing warm water year-round). Their growth is contained to the pond's surface.
Lotuses grow from a long, tuberous rhizome that grows horizontally in the mud. These rhizomes are segmented and can be broken apart for propagation. Lotuses are vigorous growers and can quickly spread in a large pond if not contained in a pot. They are hardy perennials that go dormant in winter, with the tubers surviving freezing temperatures if they are not allowed to dry out.
The fruit and seeds of these plants are unmistakably different. After a water lily flower is pollinated, its stem often coils, pulling the developing fruit underwater where it matures. The seeds are small and can be used for propagation, though they may not come true to the parent plant.
The lotus produces its famous, recognizable seed pod. This pod remains on the tall stalk after the petals fall and contains large, marble-sized seeds that are remarkably long-lived. These seeds have a very hard coat and can remain viable for hundreds of years under the right conditions. The entire pod dries and is often used in floral arrangements.
