<em>Nymphea</em>, water lily: planting and care

Description and botany

Nympheas and nuphars are often grouped under the name “water lily“, as they are closely related botanically and all belong to family Nymphaeaceae. This article deals only with genus Nymphaea, which includes around fifty different species worldwide plus many hybrids. They are perennial aquatic plants whose leaves and flowers float on the surface of water.

Mainly grown for their ornamental value thanks to their foliage and flowering, water lilies are also essential for maintaining balance in a pond by providing shade and landing surfaces for wildlife and by contributing slightly to water oxygenation.

Water lily flowers have the particular habit of opening in light and closing in darkness (a handy way to tell whether it is fine outside!). In addition, coloured flowers lighten or darken over the course of days. They are hermaphrodite and are fertilized by pollinating insects — a process known as entomogamy.

After fertilization, often three or four days after flowering begins, the pedicel coils and bends back under water where the fruit, an achene, develops. Seeds are released once ripe. They float on the surface thanks to an aril filled with air that acts like a buoy, then are dispersed by wind and currents. Later, they sink to germinate in silt. Seeds do not tolerate drying out and must remain moist. It appears that the European pond turtle (Emys orbicularis) can also disperse seeds by passing them through its digestive tract: a fine example of endozoochory.

Water lily can also reproduce asexually by fragmentation of the rootstock. All this makes the plant particularly well adapted to rapid colonisation of aquatic environments. Take care in garden ponds and small basins!

Leaves float at the surface of the water to capture solar energy. A peculiarity is that stomata, which allow gas exchange among other functions, are found only on the upper, emerged face; the lower, submerged face contains none. Leaves are produced at the end of long petioles and are cordate (heart-shaped). They are green above and more or less purple beneath. Size varies greatly by species and can range from 6 cm diameter up to over twenty centimetres. Leaves die back in winter but new shoots appear the following spring.

Nymphaea alba and Nymphaea candida (Hardy)

Found in Europe and North Africa. In the wild, white water lily (Nymphaea alba) grows in still waters, lakes or oxbow lakes. From the rootstock, sometimes more than two metres deep, emerge leaves whose laminae float on the surface. Leaves are large, more or less cordate and leathery, with well-marked lobes. The semi-double corolla consists of around twenty petals with numerous stamens bearing conspicuous yellow anthers. In France, a very similar, smaller form named boreal white water lily (Nymphaea candida) may be encountered.

Nymphaea ampla (Hardy)

Nymphaea ampla, also called white lotus or spotted water lily, grows naturally in Central and South America. It produces elegant, star-shaped, scented white flowers borne on a sturdy green stem that lifts the flower about ten centimetres above the water. Leaves are almost round with dentate margins, green in colour with soft purple edges. Despite its original range, this nymphaea is very hardy.

Nymphaea caerulea and Nymphaea capensis (Non-hardy)

Nymphaea caerulea, or blue lotus/blue water lily, is native to North Africa, notably Egypt where it was used ritually in antiquity, and bears large star-shaped flowers with pointed bluish petals. Nymphaea capensis is often confused with N. caerulea but blooms a bluer shade. Both species are non-hardy and must be overwintered during the cold season.

Nymphaea lotus and Nymphaea odorata (Non-hardy)

Nymphaea lotus, or tiger lotus/Egyptian lotus, occurs naturally from East Africa to Southeast Asia. Submerged leaves are lanceolate and streaked with brown spots; floating leaves are round and green. Flowers are star-shaped and white. Both species are non-hardy and must be overwintered during the cold season. Nymphaea odorata is highly fragrant and has very glossy leaves.

N. alba – N. ampla – N. caerulea – N. lotus

Nymphaea gigantea (Non-hardy)

Native to Australia and New Guinea, this water lily bears very large leaves (60 cm diameter) and large blue flowers (30 cm diameter).

Nymphaea tetragona (Hardy)

Present across much of the Northern Hemisphere, this is a miniature water lily producing charming cream-yellow flowers about five centimetres in diameter.

Hardy hybrid water lilies

Raised from various European and North American species such as Nymphaea alba, N. mexicana and N. odorata. These very hardy water lilies produce floating flowers in white, pink, red, yellow… up to 15 centimetres in diameter.

Tropical water lilies — day- or night-flowering (Non-hardy)

These are hybrids derived from species of African, Asian and South American tropical forests. All produce colourful blooms in red, purple, pink, yellow… some flower during the day (diurnal) while others open in the evening and at night (nocturnal). In any case, these hybrids must be overwintered in a room kept at a minimum of 10°C in winter.

N. gigantea – N. tetragona – N. ‘Attraction’ / Nelumbo nucifera (Sacred lotus)

Please note: nympheas are sometimes commonly called Lotus. Be careful, however, that Nelumbo nucifera, known as sacred lotus or Oriental lotus, is not a Nymphaea and belongs to a different family, Nelumbonaceae.

Please note also: the yellow water-lily (Nuphar lutea), a species from our flora, produces smaller yellow flowers and more elongated, less fleshy leaves.

Best varieties

Nymphaea Attraction - Water Lily

Water lily prefers good depth, at least 1 m. Flowering with vivid red petals and sepals nearly white turning garnet with age leaves no one indifferent. Very vigorous plant, only for large ponds.

• Flowering time July to October
• Height at maturity 20 cm

See the product sheet

Nymphaea Aurora - Water Lily

Hardy hybrid nymphaea of medium size, flowering reveals star-shaped semi-double flowers changing from cream to yellow, salmon-orange, then blood-red with age. Well-adapted variety for small ponds or in an aquatic container on terrace.

• Flowering time July to October
• Height at maturity 15 cm

See the product sheet

Nymphaea Colonel A.J. Welch - Water Lily

Despite its name, 'Colonel Welch' is an old French introduction, very hardy and intended for medium to large bodies of water, fairly deep (up to 1.5 m). Its flowers open in a cup, then develop into a cheerful pale yellow harmonising with golden-yellow stamens. Very vigorous water lily!

• Flowering time July to October
• Height at maturity 20 cm

See the product sheet

Nymphaea Fabiola - Water Lily

Another old French introduction of a very hardy water lily that flowers with large, very double, full blooms of superb intense pink with golden-yellow stamens. Vigour restricts it to medium to large bodies of water.

• Flowering time July to November
• Height at maturity 15 cm

See the product sheet

Nymphaea tetragona - Water Lily

Miniature water lily indispensable in small ponds or even in tubs and barrels on terrace. Bears star-shaped semi-double white flowers with yellow-orange stamens. A true little jewel to admire and pamper.

• Flowering time July to October
• Height at maturity 10 cm

See the product sheet

Planting water lilies

Where to plant?

In water! But in a very sunny position because water lilies need at least six hours’ sunshine to flower well. They take up quite a bit of space, allow 1 m² per plant, and do not like being jostled: protect them from wind and any splashing. On a terrace, for example, you can plant a single water lily in a container at least 1 m wide and 45 cm deep: old washtub, trough, old barrel…

When to plant?

You can place the hardiest water lilies in water from mid‑March through September. For less hardy varieties, wait until June before placing them in a pond.

How to plant?

Install water lilies in pockets of clay soil prepared on the bottom of the pond or, more easily, in baskets specially designed for aquatic plants. These have the advantage of being easy to place and… to remove if you need to move the plant. In addition, this will prevent your water lilies from spreading too much.

• Fill the baskets with good clay soil or with potting compost for aquatic plants (sold in garden centres) that contains a significant proportion of clay. Do not try another substrate (general‑purpose compost, soil that is too light, …) because it will disperse in the water and will not stay in the basket. Also avoid substrates that are too rich in nitrogen which will cause the water lily to produce excessive foliage at the expense of flowering. Instead use long‑lasting fertiliser tablets designed for this purpose.
• Place a single water lily rootstock at an angle in the basket filled with clay soil. Make sure the terminal bud points upwards but do not cover it with soil. Take care not to break the roots, which are quite fragile.
• Immerse the basket in a bucket of water to thoroughly soak the clay substrate. If you plan to put your water lily in a pond with fish, consider covering the top of the basket with gravel and large stones so the fish do not rummage in the soil and dirty the water.
• Place the basket for a few days in a shallow part of the pond. The water lily will start growing fairly quickly. When this happens, you can gradually lower the plant into the water to its final position.

→ Learn more in Planting water lilies and Installing a water lily in a small pond on a balcony or a terrace.

Planting a water lily in a basket

Care and maintenance

Care

For hardy water lilies :

• In summer, remove some surface leaves if foliage becomes too vigorous. Leaves of no plant should obscure more than two-thirds of pond or basin surface, otherwise flora and fauna may die. Excessive shade also encourages algal proliferation.
• In autumn, remove all yellowing leaves to prevent them rotting and accelerating silting of the water feature.

For less-hardy water lilies :

• They need same care as above but…
• they should be lifted out of water in October and overwintered in a water-filled container kept at a minimum temperature of 10°C. Plants can return to pond or pool outdoors during May, or even June.

All water lilies need fertilisation because they are fairly greedy plants. Use fertiliser tablets for aquatic plants designed for this purpose and press them into pot soil in spring.

Possible diseases

Black aphids can cover stems and flower stalks above the water during warm, humid springs. If very numerous, they can weaken plant by feeding on its sap. Fortunately, aphids have never learned to swim and are hopeless at breath‑holding contests. In that case, dip leaves under water for a few minutes: guaranteed effective.

Insects such as water‑lily beetle (Galerucella nymphaeae), a small beetle of family Chrysomelidae, and water‑lily moth (Elophila nymphaeata), a moth of family Crambidae, can attack water‑lily leaves without causing serious harm to plant. Both species are associated with water lilies and therefore have their place. If you find any, it will be proof your garden is natural.

Yellow spots on leaves that quickly turn black and lead to leaf death are a warning that water lily is not grown in ideal conditions. To prevent development of fungi and moulds, place water lily in sun and do not cover terminal bud with soil. Planting too close together can also be problematic, so allow for space each water lily will occupy before planting.

Propagation by division

Sowing is very complicated and should be reserved for professionals to obtain new varieties by hybridization.

However, it is perfectly possible to divide the rootstock when the plant begins to flower less, on average every four years. Carry out operation in early spring or at end of flowering.

Take basket out of water and rinse with water to reveal rootstock. Cut pieces of secondary rootstock at least ten centimetres long, making sure these pieces include a terminal bud; leaves will emerge from there, and a few well-developed roots. Replant this piece of rootstock promptly as indicated in the section on planting.

→ Learn more about dividing water lily in our tutorial page

Pairing water lilies

In a large pond

A beautiful colony of Nymphea hybride ‘Attraction’ will be splendour in a large pond populated by koi carp. The koi will find welcome shade on the hottest days of the year, while the plants will reduce impact of black aphids: a kind of mutualism. Obviously, in a large pond plant choice can be quite extensive; floating, submerged or marginal aquatic plants can be used. For example, a white Thalia, with Canna-like appearance, will bring a pleasing vertical element to the pond. Or this striking Orontium or Candle plant, whose characteristic habit, with spadix-type flowering, will contrast beautifully with the Nymphaeas. A handsome clump of variegated Glyceria at the pond edge will contribute to an impression of lush vegetation.

An example of a planting combination in a large pond: Nymphea hybride ‘Attraction’, Glyceria maxima ‘Variegata’, Thalia dealbata and Orontium aquaticum

In a natural pond

A natural pond should remain… natural, so favour robust plants and, where possible, species from local flora. Most will appear surprisingly of their own accord: cattail, rush, water mint, marsh forget-me-not… Still, try this charming little Nymphea ‘Aurora’ with semi-double, star-shaped flowering that progresses from cream to yellow, salmon-orange, then blood-red as it ages. On the edges, water plantain and flowering rush will enliven pond sides. A handsome clump of marsh iris will brighten edges from April to June, along with some meadowsweet set slightly further back, another native that likes very wet soil. A fine Lythrum salicaria ‘Robert’ will complete the picture.

An example of a planting combination in a natural pond: Nymphea ‘Aurora’, Filipendula ulmaria, Alisma plantago, Iris pseudacorus and Lythrum salicaria ‘Robert’

In a mini aquatic garden on the terrace

You can easily create a mini aquatic garden in an old trough, a vintage zinc washing tub or any watertight container at least 50 cm deep and 1 m in diameter. In this case favour quality over quantity by choosing only aquatic plants of compact growth but high aesthetic potential. For example this miniature water lily, Nymphaea tetragona, ideal for small volumes. Add a neat small clump of mare’s tail, Hippuris vulgaris, which will oxygenate and purify water (note, however, that it can become somewhat invasive, so manage it by removing shoots). To add a little verticality, try a flowering rush, Butomus umbellatus, a charming shallow-water flowering perennial that can be grown in a pot.

An example of a container combination: Nymphaea tetragona, Butomus umbellatus and Hippuris vulgaris

Did you know?

• Water lilies are indicator species of the quality of water in a medium.
• Some Native Americans, notably those of the Ojibwe tribe, consumed the flower buds of Nymphaea
• Nymphea caerulea and Nymphea lotus were sacred in ancient Egypt. They symbolised the god Râ (the sun) because their flowers opened during the day and closed at night.
• In 1889, at the Paris World’s Fair (the one that gave us the Eiffel Tower…), the first hybridiser of water lilies, Joseph Bory Latour-Marliac, demonstrated his production. Claude Monet, who happened to be passing by, fell in love with them. So much so that they still bloom in the ponds of the gardens at Giverny and Monet’s most famous series, no fewer than 250 paintings, is called… the Water Lilies.
• Latour-Marliac’s nursery still exists and still offers a wide variety of water lilies.