Ornamental · Nymphaeaceae
Water Lily
Nymphaea
Offer it steady sun and calm water, and the water lily will open flower after flower from late spring into fall.
Full sun
USDA 3–11
3–10 in · 8–25 cm
Overview
If a pond has you feeling unsure, the water lily is a kind place to begin. It is a true aquatic, so its roots settle into a submerged pot of heavy soil while its round pads and cupped blooms rest right on the surface. It shares a name with the true lilies but none of their family ties, which is welcome news if a cat shares your home.
You will meet two main groups, and both are easy to love. The hardy lilies return on their own each year across zones 3 to 11, riding out hard winters as long as the crown rests below the ice. The tropical lilies bring deeper blues and purples and even flowers that open at night, though they are tender, so most gardeners simply enjoy them as annuals where the water freezes.
What the plant asks of you is short and easy to remember: good light and water that stays calm. Settle it into a bright, quiet spot well away from any fountain, and it will fan its pads out and bloom for months. Miss the sun or let the water churn, and you get plenty of leaves and few flowers, though nothing here is hard to put right.
Care
The short version: give it full sun and still water, with the crown tucked into 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, and it will keep flowering happily for you.
Light
Water lilies flower for the sun, so aim to give them at least 6 hours of direct light each day, and full sun will reward you with the most blooms. They will get by in partial shade, but expect more pad than flower, and that is perfectly fine while you find a brighter spot.
Water
This is a true aquatic that lives happily in standing water, its crown resting in a submerged pot while the pads float above. Try for around 6 to 18 inches (15 to 46 cm) of water over the crown, depending on the cultivar, and keep that water calm. Fountains and pumps ripple the surface, and a water lily would much rather sit still.
Soil
Settle the crown into heavy clay loam or aquatic media in a submerged container, then top it with gravel to keep the soil in place. Anything from 6.0 to 8.0 on the pH scale suits it well, so lean on a good heavy mix and try not to worry over the exact acidity.
Temperature
Hardy water lilies are wonderfully tough, holding steady from about -40°F to 100°F (-40°C to 38°C) as long as the crown stays below the winter ice line. Just set the pot deep enough that the crown never freezes solid, and it will come through the cold.
Humidity
Floating on open water, a water lily already sits in high humidity, so there is nothing here for you to fuss over. The pond quietly takes care of it for you.
Feeding
These are hungry plants with healthy appetites. Press an aquatic fertilizer tablet into the soil beneath the gravel about once a month through spring and summer, and that steady feeding is what turns a shy bloomer into a generous one.
Pruning
A little tidying goes a long way. Pinch away spent flowers and yellowing pads as they show up to encourage fresh bloom and keep the water clear of rotting leaves, and the plant will look after the rest.
Repotting
Rather than repotting in the usual way, a water lily simply asks for dividing every few years. When blooms taper off, the pads start rising up out of the water, or the container fills with rhizomes, that is your gentle signal to lift and split the clump.
Size & spacing
The plant stays low, sitting just 3 to 10 inches (8 to 25 cm) above the water, yet its pads reach out wide, somewhere from 2 to 12 feet (61 cm to 3.7 m) across depending on the cultivar. Pick a lily whose spread suits your pond, and it will fill the space without swallowing the whole surface.
When to plant
A water lily takes its cue from warm water rather than a date on the calendar. Lower the rhizomes into their submerged pots in spring, once the chill has eased and the water is warming, and from late spring through fall you will see flowers opening 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
Nearly every water lily worry traces back to one of a few gentle fixes: not enough sun, a crown set at the wrong depth, or a clump that has simply outgrown its pot, plus the small handful of pests that visit the pads. Catch the early signs below and you can set things right long before the flowers fade. Look closely, then act while it still counts.
Plenty of pads but hardly any flowers
When a water lily leafs out yet holds its flowers back, the gentle culprit is usually too much shade, less than the 6 hours of direct sun it needs to set buds. A crown planted too deep, a clump that has outgrown its pot, or water stirred by a fountain can all keep blooms shy 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, and the flowers will come.
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 the pads and buds
Those little clusters are waterlily aphids, soft-bodied insects that settle on the tops of the pads and on the flower buds. Happily the fix is easy, since a rinse or brush knocks them off into the water, where they cannot climb back and the fish are glad to eat them. If a pad is truly covered, just pull it and move on.
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 chewed through with holes
A few evenly yellow old pads are simply age and nothing to fret about. Ragged holes and nibbled edges usually mean waterlily beetle, leaf-mining midges, or china-mark moth are feeding, while spots or soft brown patches can point to leaf spot or crown rot. Trim off the marked pads, pick off any beetles and larvae or flick them into the water, and slip in a fertilizer tablet if the plant seems hungry.
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
Here is a reassuring note for anyone with pets: this is a water plant you can relax about. The water lily is not a true lily, so it carries none of the kidney danger that real lilies and daylilies bring to cats. It sits comfortably off the ASPCA toxic list, and cats, dogs, and everyone else in the house stay safe beside it.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Safe around cats. Because the water lily is not a true lily, it carries none of the kidney risk that makes Lilium and daylilies so dangerous to them, so a curious cat is fine near it.
Dogs None
Nothing to worry about for dogs. Should a pet wade in and mouth a floating pad, it will come to no harm at all.
Horses Safe
Not listed as any hazard to horses, and a pond plant seldom finds its way within a horse's reach in the first place.
Rabbits Safe
Safe for rabbits too, with no toxic compounds that would trouble a nibbling one.
Livestock Safe
Cattle, goats, and sheep can graze around a pond in peace, with nothing to fear from the leaves or flowers.
Birds Safe
Harmless to birds and waterfowl, which happily pick at the pads and seeds out in the wild.
People Safe
No danger to people, children included, even when small hands 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
There are hundreds of water lilies to explore, sorted into the hardy kinds that winter over in the pond and the tender tropicals prized for richer color. A few are especially worth knowing by name as you begin.
'Attraction'
A much-loved hardy lily for zones 3 to 8, it opens fragrant red flowers and remains one of the most widely grown choices around.
'Marliacea Chromatella'
This hardy lily thrives in zones 4 to 10, lifting canary-yellow cupped flowers over copper-mottled pads and blooming from May right until frost.
'Director George T. Moore'
A tropical day-blooming lily, it raises violet-blue flowers above the water and is grown as an annual wherever winters turn cold.
Tropical day- and night-blooming water lilies
These tender Nymphaea suit zones 9 to 11 or a season as annuals, offering blue and purple shades and night-opening flowers that no hardy lily can give you.
Lotus (Nelumbo)
Despite the company it keeps, this is not a water lily but a separate genus in its own family, holding round leaves and flowers high above the water instead of floating them on the surface.
How to propagate
Making more water lilies is refreshingly simple, and nearly everyone leans on the same friendly method, dividing a plant they already have rather than fussing with seed.
DivisionEasy
Spring · One growing season
Dividing in spring is the usual and easiest way to make more water lilies. Lift the rhizome, cut it into pieces that each keep a growing point, and replant them lying flat with the bud end up in a submerged pot of heavy soil. Each section finds its feet over a single growing season, so divide every few years once the clump crowds itself and the flowers start to thin.
SeedModerate
Spring to summer · One or more seasons
Seed is an option for the wild species and can take a season or more to get going, sown in spring or summer. For the garden it is rarely worth the wait, since most named cultivars are sterile hybrids that will not come true, and they are far happier split by division.
Myths
Water lilies are true lilies, so they must be just as deadly to cats as the lilies that cause kidney failure.
The water lily (Nymphaea) is not a true lily and stands well outside that dangerous group. The plants that trigger sudden, often fatal kidney failure in cats are the true lilies (Lilium) and daylilies (Hemerocallis), which are not related to it. A water lily in your pond is safe on this count, and it does not appear on the ASPCA toxic list. Do keep the real lilies and daylilies away from cats, but know that this aquatic plant is a different thing entirely.