Ornamental · Nymphaeaceae
Water Lily
Nymphaea
In a still, sunny pond, the water lily unfolds a season of flowers from late spring to fall.
Full sun
USDA 3–11
3–10 in · 8–25 cm
Overview
Few things transform an outdoor space like a water lily resting on open water. It is a true aquatic, its roots hidden in a submerged pot while the pads and cupped flowers compose a floating still life across the pond. And for all the name suggests, it is no relation to the true lilies, a happy detail in a home with a cat.
The choice comes down to mood. Hardy lilies settle in for the long term across zones 3 to 11, returning each year to anchor the pond through the seasons. Tropical lilies turn up the drama with deeper blues and purples and flowers that open into the evening, though they are tender and often kept for a single glamorous summer where winters bite.
What it wants from a setting is refreshingly simple: a sunlit corner and water left perfectly still. Give it a bright, calm stretch of pond away from any fountain and it becomes the quiet centerpiece of the garden for months. Set it in shade or restless water, though, and the effect falls flat, all foliage and little flower.
Care
The short version: choose a sunlit, still stretch of pond and settle the crown in a pot of heavy soil under about 6 to 18 inches of water. Feed it monthly through the growing season and divide the clump every few years to keep the display in full flower.
Light
Sun is what a water lily lives for, so give it at least 6 hours of direct light a day, with full sun bringing the fullest display of flowers. A shadier corner will keep it alive, but the show turns to leaf and the blooms grow scarce.
Water
This is a true aquatic that makes its home in standing water, the crown tucked into a submerged pot while the pads compose themselves across the surface. Allow roughly 6 to 18 inches (15 to 46 cm) of water over the crown to suit the cultivar, and keep the surface calm. Fountains and moving water break the stillness this plant depends on.
Soil
Set the crown into heavy clay loam or aquatic media in a submerged container, finished with a layer of gravel that keeps the water clear. A pH anywhere from 6.0 to 8.0 will do, so the mix itself matters far more than any fuss over acidity.
Temperature
Hardy water lilies weather a wide range, from about -40°F to 100°F (-40°C to 38°C), provided the crown rests below the winter ice. Position the pot deep enough that the crown never freezes solid and the plant returns each spring.
Humidity
Living on open water, a water lily is always wrapped in high humidity, so this is one care detail that simply looks after itself. The pond does the work.
Feeding
A water lily is a generous feeder that repays generous feeding. Slip an aquatic fertilizer tablet into the soil beneath the gravel about once a month through spring and summer, and the difference shows in a display that never seems to pause.
Pruning
A little attention keeps the picture pristine. Lift away spent flowers and yellowing pads as they appear, and the plant rewards you with fresh bloom and a clean, uncluttered surface.
Repotting
Rather than repotting, a water lily asks only to be divided every few years. When the flowers thin, the pads begin to crowd upward, or the container fills with rhizomes, it is time to lift and split the clump and restore the display.
Size & spacing
The plant stays low against the water, only 3 to 10 inches (8 to 25 cm) high, while its pads reach outward from 2 to 12 feet (61 cm to 3.7 m) across depending on the cultivar. Choose one whose spread flatters your pond so it frames the water rather than covering it.
When to plant
A water lily keeps its own calendar, one written by the warmth of the water rather than the date. Lower the rhizomes into their submerged pots in spring, once the chill has passed and the pond begins to warm, and the flowers arrive to carry the garden from late spring through fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Set rhizomes or tubers in submerged containers in spring once water has warmed and frost danger has passed.
- Harvest: Late spring through fall (flowers rest on or just above the water).
Hardiness
USDA hardiness zones: 3–11
Temperature: down to -40°C
Troubleshooting
When a water lily underperforms, the reasons are usually few and easily read: too little sun, a crown at the wrong depth, or a clump grown crowded, along with the odd pest on the pads. Catch the early signals below and the display recovers before it ever falters. Match what you notice, then set it right.
A lush spread of pads with the flowers missing
When the pads flourish but the flowers stay away, the culprit is usually too much shade, less than the 6 hours of direct sun the plant needs to set buds. A crown sunk too deep, a clump grown crowded, or the restlessness of a nearby fountain can dull the display as well. Move it into full sun and still water, lift it to the right depth, divide a crowded rhizome, and feed it through the season to bring the flowers back.
Fix:
- Move the container so the plant gets at least 6 hours of direct sun
- Raise the container so the crown sits at the recommended depth for the cultivar
- Lift and divide the rhizome every few years
- Relocate away from fountains or pump outflow so the plant sits in still water
- Fertilize with aquatic plant tablets during the growing season
Soft green clusters gathering on pads and buds
Those clusters are waterlily aphids, small soft-bodied insects that settle across the pads and the flower buds. The remedy is refreshingly low effort: rinse or brush them into the water, where they cannot climb back and the fish are glad to take them. A pad past saving is best simply removed.
Fix:
- Hose or brush the aphids off the pads into the water, where they cannot climb back and fish may eat them
- Remove and discard heavily infested pads
Pads yellowing or opened up with holes
A few evenly yellowed old pads are nothing more than age. Ragged holes and chewed edges point to waterlily beetle, leaf-mining midges, or china-mark moth at work, while spots or soft brown patches may mean leaf spot or crown rot. Clear away the marked pads, lift off any beetles and larvae or drop them into the water, and add a fertilizer tablet if the plant looks underfed.
Fix:
- Remove and discard yellow, spotted, or chewed pads
- Pick off beetles and larvae or knock them into the water
- Fertilize with aquatic plant tablets if a deficiency is suspected
Toxicity
For a household with pets, this is a reassuringly easy plant to live with. The water lily is not a true lily, so it carries none of the kidney danger that real lilies and daylilies hold for cats. It sits off the ASPCA toxic list, and cats, dogs, and the rest of the household share the garden with it in peace.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Safe in the company of cats. Being no true lily, it holds none of the kidney risk that makes Lilium and daylilies so perilous to them.
Dogs None
An easy plant to keep around dogs. A pet that wades in and mouths a floating pad has nothing to fear from it.
Horses Safe
Not counted among hazards to horses, and a pond plant rarely finds its way within their reach in any case.
Rabbits Safe
Safe for rabbits as well, carrying no toxic compounds that would trouble them.
Livestock Safe
Cattle, goats, and sheep can graze beside the water untroubled by the leaves or flowers.
Birds Safe
Harmless to birds and waterfowl, which in the wild happily pick at the pads and seeds.
People Safe
No danger to people, children included, even as small hands reach across the water to the floating flowers.
Grown in an outdoor pond, so casual contact by pets or children is uncommon; no special handling required.
Varieties
Hundreds of water lilies exist to suit any pond and any taste, divided between the hardy kinds that stay year to year and the tender tropicals kept for their richer palette. A handful stand out as worth knowing.
'Attraction'
A hardy classic for zones 3 to 8, it opens fragrant red flowers and remains one of the most beloved choices for any pond.
'Marliacea Chromatella'
Hardy across zones 4 to 10, it sets canary-yellow cupped flowers over copper-mottled pads and carries the display from May until frost.
'Director George T. Moore'
A tropical day-bloomer that lifts violet-blue flowers just above the water, grown as an annual wherever the winters run cold.
Tropical day- and night-blooming water lilies
Tender Nymphaea for zones 9 to 11, or a single summer as annuals, bringing blues and purples and evening-opening flowers the hardy lilies never offer.
Lotus (Nelumbo)
Not a water lily but a genus of its own family entirely, holding its round leaves and flowers high above the water instead of resting them on the surface.
How to propagate
Growing your collection is an unhurried pleasure, and nearly everyone takes the same easy path, dividing a plant already in the pond rather than raising it from seed.
DivisionEasy
Spring · One growing season
Dividing in spring is the customary and simplest way to expand a water lily planting. Lift the rhizome, part it into sections that each keep a growing point, and settle them flat with the bud end up in a submerged pot of heavy soil. Each piece establishes across a single growing season, so plan to divide every few years once the clump grows crowded and the flowering fades.
SeedModerate
Spring to summer · One or more seasons
Seed suits the wild species and asks for a season or more before it matures, sown in spring or summer. For the ornamental pond it rarely justifies the wait, since most named cultivars are sterile hybrids that will not come true and are far better increased by division.
Myths
A water lily is a true lily, so it must be as deadly to cats as the lilies that cause kidney failure.
In truth the water lily (Nymphaea) is not a true lily and stands entirely apart from that dangerous group. The plants behind sudden, often fatal kidney failure in cats are the true lilies (Lilium) and daylilies (Hemerocallis), which share no kinship with it. A water lily on the pond holds no such threat, and it never appears on the ASPCA toxic list. Keep genuine lilies and daylilies away from cats, but let this aquatic plant stand on its own.