The water lotus is an emergent aquatic plant with cultural and ornamental value. A fantastic perennial for fish and wildlife ponds, it comes in just two extant species – the sacred lotus (N. nucifera) and the American lotus (N. lutea). The sacred lotus is native to Asia, whereas the American lotus is naturally found in North America, the Caribbean, and Honduras. Both are classified under the Nelumbo genus, which is the only member of the Nelumbonaceae family.
Due to the waterlily-like features of water lotuses, they were once included in Nymphaeaceae. Recent genetic studies have shown that lotuses are quite unique, and their features are only similar to waterlilies as a result of convergent evolution. Like those of the latter, water lotus roots anchor the plant to the substrate while their leaf stalks grow toward and through the water’s surface. Their circular leaves may be either floating or emergent as their stalks can grow up to 6.6 feet (2 meters) long!
Water lotus blooms possess papery thin petals, which range in color from white to pink and yellow. They are borne on thick stems that rise a few inches above the large leaves. Fully opened blooms may measure as wide as 11 inches (28 cm) across and have dozens of petals each. Once pollinated, they develop into seed pods. In terms of appearance, these pods resemble the multi-holed spouts of watering cans!
Facts, Benefits & Uses of Water Lotus
The water lotus can dramatically enhance the appearance of both ornamental and wildlife ponds. Its delicate spring buds and blooms pleasantly contrast the deep green leaves. Ultrahydrophobic, the leaves often glimmer with raindrops that roll off of their surfaces and into the water at the slightest disturbance. The leaves’ hydrophobic nature allows them to respire efficiently.
Another interesting, functional feature of water lotuses is their ability to thermoregulate their blooms. This adaptation, which is basically the generation of heat, likely developed as a means to attract more pollinators. Many theories abound as to the main purpose of this feature, but the generated heat is lost as soon as fertilization of the ovary occurs.
Like other submersed, floating-leaved or emergent plants, this species performs several ecological roles in ponds. While it helps provide shade, thereby regulating water temperature and preventing algal growth, it serves as an important resting place and source of food for many animals.
Water Lotus Growth, Hardiness & Climate
Water lotus is suitable for shallow to moderately deep ponds as its roots can tolerate depths of up to 8 feet (2.4 meters). Young plants generally have a better growth response in warm water, which stimulates desirable flowering rates. This plant’s seeds can only germinate in temperatures above 13˚C (55˚F), so they may fail to become established in areas where the water freezes over. Most cultivars need to be grown in a mild temperature range of 23 – 27˚C (73 – 81˚F).
In the wild, stands of water lotus are usually found in slow-moving rivers, streams, and deltas, where individual plants are anchored by a network of rhizomatous roots. In mud, these can naturally spread on their own. The production of seeds allows for a wider dispersal of water lotus populations. The seasonal production of thousands of seeds, which can go dormant and remain viable for years, results in new colonies wherever conditions are optimal.
Hardy to USDA zones 4 – 10, N. nucifera and N. lutea require around 6 hours of sunlight per day. They can survive in partly shaded areas, though the lack of light may bring about stunted leaves and may hinder bud production. Both species and their cultivars thrive best in full sun, warm temperatures, and freshwater bodies with rich nutrient profiles.
How to Plant Water Lotus
Water lotus is rarely cultivated with seeds and is instead grown by planting intact tubers. To prevent their major growth points (eyes) from breaking off, they need to be handled gently and transported with care. As soon as you are able to acquire good-quality tubers, make sure to store them in a moderately warm area. They can be planted directly into the shallow margins of slow-moving, outdoor ponds, ideally during summer.
When deciding on a permanent spot for a water lotus, make sure that the available space can easily accommodate a fully grown plant. Tubers should be planted in round and deep pots or containers, where their roots can be restricted yet have enough room to grow downwards. Pots that are too small may stunt plant growth and force the roots to grow over the sides and into the pond’s substrate. Fill the pot with a sandy-clay substrate mixture, leaving about 3 – 4 inches (7.6 – 10.2 cm) of room from the top rim.
Place the tuber on the substrate and cover it with sand until the contents are level with the rim. To keep the sand particles and the tuber in place, you can top the pot with stones. Carefully lower the pot into your pond or water feature. To promote upright growth, the soil surface should be around 6 – 12 inches (15 – 30 cm) below the water’s surface. New leaves should appear after just 2 – 3 weeks of growth! For best results, plant tubers in mid-spring or when ambient temperatures are most agreeable.
How to Care for Water Lotus
Once aerial leaves and lengthier leafstalks begin to appear, you can feed the plant by lodging fertilizer tablets into the substrate. This isn’t absolutely necessary in fish ponds where nutrient levels should naturally be high, but it should help increase flowering rates. In the succeeding spring, make sure that the water temperature remains at about 25˚C (77˚F) or more to induce flowering. The foliage should also consistently be exposed to full sun.
Remove all spent blooms and yellowing leaves before they begin to decompose on the pond’s surface. Inspect the leaves for pests and diseases, making sure to get rid of or treat parts that have been compromised. If all is well, you should aim to repot your plant every 2 – 3 years. This should refresh the existing, active tubers and allow for the thorough removal of dead plant material.
How to Winter Water Lotus
In temperate zones, water lotuses need to be overwintered properly to survive through the coolest months of the year. Actively growing plants will naturally have slower growth rates in fall, during which their leaf stalks should be cut down before they die back. Move the pot into deeper parts of the pond, where water temperatures will remain slightly higher than that of the surface through winter. The pots should be deep enough to keep the tubers free of ice.
For as long as temperatures remain cool, the tubers will remain dormant. Come spring or as soon as temperatures begin to rise once more, the tubers may exit dormancy and begin to produce new leaf stalks. You can then move the pots back to their original positions, where the leaf stalks can be exposed to more intense sunlight.
Is Water Lotus Invasive or Toxic?
As both N. nucifera and N. lutea are able to spread via a network of rhizomes that can grow quickly in warm temperatures and nutrient-rich conditions, they have the potential to be invasive plants. These species also produce pods that can release thousands of highly viable seeds. If they are dispersed into unsuitable locations, these have the capacity to become dormant for years. Once they are exposed to warm temperatures and moisture, however, they can quickly germinate to produce large colonies.
N. nucifera, in particular, has been introduced into regions outside of its native range. Its escape from cultivation has caused exotic colonies to inhibit the growth of native aquatic plants, decreasing biodiversity in many freshwater systems. These colonies can be dense enough to create light-blocking mats of vegetation that may significantly hinder boating and swimming-related activities. To prevent this species from overgrowing your water feature, restrict its roots to within pots or containers.
Although water lotuses have been used in folk medicine due to their active substances, they are not considered toxic plants. In reasonable quantities, their plant parts can be safely ingested, especially if they have been cooked beforehand.
Is Water Lotus Edible? Do Animals Eat it?
Both species of water lotus are edible, though N. nucifera is more commonly consumed, as it is a culturally important ingredient in some Asian dishes. It is extensively farmed for the production of its starch-rich rhizomes and protein-rich seeds. Wildlife, including fish, will readily partake in the plants’ foliage, seeds, and roots in the absence of other food sources.
Where to Buy Water Lotus & Seeds? (UK & US)
Nelumbo tubers and seeds can usually be purchased from plant nurseries that carry aquatic species. These come in large, medium, and dwarf-sized cultivars, so it would be best to gauge the size that would suit your water feature before making a purchase. Keep in mind that N. nucifera is listed as an invasive species in some states, where its sale and cultivation may be prohibited.
