Ornamental · Nymphaeaceae
Water Lily
Nymphaea
Give it a sunny pond and still water, and the water lily floats out flowers from late spring to fall.
Full sun
USDA 3–11
3–10 in · 8–25 cm
Overview
A water lily turns a plain pond into something worth sitting beside. It is a true aquatic, with its roots anchored in a submerged pot of heavy soil and its round pads and cupped flowers floating right on the surface. Despite the name it is no relation to the true lilies, which matters a great deal for anyone with a cat.
Gardeners reach for two main kinds. The hardy types come back year after year through zones 3 to 11 and shrug off cold winters as long as the crown sits below the ice. The tropical types push out bolder blues and purples and even night-opening flowers, but they are tender and most people grow them as annuals where the water freezes.
What a water lily asks for is simple and non-negotiable: plenty of sun and water that sits still. Give it a bright spot and a calm pond away from any fountain, and it spreads its pads wide and blooms for months. Skip the sun or set it in moving water, and you get a raft of leaves with almost no flowers.
Care
The short version: full sun and still water, with the crown set 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 flowers coming.
Light
Water lilies bloom for the sun and want at least 6 hours of direct light a day, with full sun giving the most flowers. They will limp along in partial shade, but expect far fewer blooms and a lot more leaf.
Water
This is a true aquatic that lives in standing water, with the crown set in a submerged pot and the pads floating above. Aim for roughly 6 to 18 inches (15 to 46 cm) of water over the crown depending on the cultivar, and keep it still. Fountains and pumps stir the surface, and a water lily hates moving water.
Soil
Plant the crown in heavy clay loam or aquatic media packed into a submerged container, topped with gravel to hold the soil down. A pH anywhere from 6.0 to 8.0 suits it, so the soil mix matters far more than fussing over acidity.
Temperature
Hardy water lilies are tough, holding on from about -40°F to 100°F (-40°C to 38°C) as long as the crown stays below the ice line through winter. Set the pot deep enough that the crown never freezes solid.
Humidity
Sitting on open water, a water lily lives in high humidity by default, so there's nothing to manage here. The pond takes care of it.
Feeding
These are hungry plants. Push an aquatic fertilizer tablet into the soil below the gravel about once a month through spring and summer, and feeding is the difference between a few flowers and a steady run of them.
Pruning
Keep up with the dead. Pinch off spent flowers and yellowing pads as they appear to push repeat bloom and keep the water clean of rotting leaves.
Repotting
A water lily needs dividing every few years, not repotting in the usual sense. When flowering drops off, the pads start standing up out of the water, or the container fills with rhizomes, it's time to lift and split the clump.
Size & spacing
The plant itself stays low, just 3 to 10 inches (8 to 25 cm) above the water, but the pads spread wide, anywhere from 2 to 12 feet (61 cm to 3.7 m) across depending on the cultivar. Match the spread to your pond so it doesn't blanket the whole surface.
When to plant
A water lily wakes up with warm water, not the calendar. Set the rhizomes into their submerged pots in spring once the cold has lifted and the water has begun to warm, and from late spring through fall the flowers open across the surface.
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
Most water lily trouble comes down to too little sun, the wrong planting depth, or a clump that has crowded itself, and the rest is the handful of pests that live on the pads. Read the early signs below and you can put things right before the show stops. Match what you see, then act while it still helps.
Lots of leaves but few or no flowers
Water lilies bloom for the sun, so the usual culprit is too much shade, less than the 6 hours of direct light they need to set buds. A crown buried too deep, a clump that has outgrown its container, or moving water from a fountain will all hold blooms back too. Move the plant into full sun and still water, raise it to the right depth, divide a crowded rhizome, and feed it through the season.
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 massed on the pads and buds
Those clusters are waterlily aphids, small soft-bodied insects that gather on the upper leaf surface and the flower buds. The fix is simple: hose or brush them off into the water, where they can't climb back and the fish often eat them. Pull any pad that's badly covered.
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 turning yellow or chewed full of holes
A few uniformly yellow old pads are just age and nothing to worry about. Ragged holes and chewed edges point to waterlily beetle, leaf-mining midges, or china-mark moth feeding, while spotting or soft brown patches can mean leaf spot or crown rot. Cut away the marked pads, pick off any beetles and larvae or knock them into the water, and add a fertilizer tablet if the plant looks starved.
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
Good news for pet owners: this is one water plant you don't need to worry about. The water lily is not a true lily, so it carries none of the kidney danger that real lilies and daylilies pose to cats. It sits safely off the ASPCA toxic list, and cats, dogs, and the rest of the household are fine around it.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Safe around cats. The water lily is not a true lily and carries none of the kidney risk that makes Lilium and daylilies so dangerous to them.
Dogs None
No concern for dogs. A pet that wades in and mouths a floating pad has nothing to fear from it.
Horses Safe
Not listed as a hazard to horses, and a pond plant rarely ends up within their reach anyway.
Rabbits Safe
Considered safe for rabbits, with no toxic compounds that would trouble them.
Livestock Safe
Cattle, goats, and sheep can graze near a pond without risk from the leaves or flowers.
Birds Safe
Harmless to birds and waterfowl, which often pick at the pads and seeds in the wild.
People Safe
Poses no danger to people, including children who reach into the water to touch 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, split between the hardy lilies that overwinter in the pond and the tender tropicals grown for their bolder colors. These are the ones worth knowing by name.
'Attraction'
A hardy favorite for zones 3 to 8 that opens fragrant red flowers and stays one of the most widely planted cultivars.
'Marliacea Chromatella'
A hardy lily for zones 4 to 10 with canary-yellow cupped flowers and copper-mottled pads that bloom from May until frost.
'Director George T. Moore'
A tropical day-blooming type that lifts violet-blue flowers above the water and is grown as an annual where winters turn cold.
Tropical day- and night-blooming water lilies
Tender Nymphaea for zones 9 to 11, or grown as annuals, that bring blue and purple shades and night-opening forms no hardy lily can match.
Lotus (Nelumbo)
Not a water lily at all but a separate genus in its own family, holding round leaves and flowers high above the water rather than floating them on the surface.
How to propagate
Water lilies are easy to multiply, and almost everyone does it the same way, by splitting a plant they already grow rather than starting from seed.
DivisionEasy
Spring · One growing season
Division in spring is the standard way to multiply a water lily and the easiest. Lift the rhizome, cut it into sections that each carry a growing point, and replant them horizontally with the bud end up in a submerged container of heavy soil. Each piece settles in over a single growing season, so divide every few years once the clump crowds itself and flowering falls off.
SeedModerate
Spring to summer · One or more seasons
Seed works for the wild species and can take a season or more to come along, sown in spring or summer. It's rarely worth the wait for the garden, though, because most named cultivars are sterile hybrids that won't come true and are far better split by division.
Myths
Water lilies are true lilies and so are deadly to cats, like the lilies that cause kidney failure.
The water lily (Nymphaea) is not a true lily and is not part of the dangerous group at all. The plants that cause sudden, often fatal kidney failure in cats are true lilies (Lilium) and daylilies (Hemerocallis), which are unrelated. A water lily in your pond poses no such risk, and it isn't listed among ASPCA toxic plants. Keep the real lilies and daylilies away from cats, but don't confuse them with this aquatic plant.