Taxonomy and origin
The peace lily is not a true lily. It belongs to the arum family, Araceae, alongside caladiums, elephant ears and callas. What everyone calls the flower is an inflorescence: a leaf-like spathe wrapped around a spike-like spadix. The white hood is a modified leaf, which is what the genus name means in Greek, spathe leaf, and the tiny true flowers sit on the cream spadix inside it. Those sail-like blooms stand 4 to 12 inches above the foliage. The leaves run 4 to 25 inches long and 1 to 10 inches wide in a basal rosette, so a mature plant reads as a mound of leaves rising from one crown. Plant tags still sell the same species as spath, spathe flower, white sails or white anthurium, the last of those borrowed from a different aroid, which is how peace lily and anthurium end up confused on the same shelf.
Species grow wild in humid understory shade in Panama, Colombia, Ecuador, Venezuela, Costa Rica, the Philippines and the Malay Archipelago, and the wider range takes in Mexico and islands of the western Pacific. Counts of the genus run from about 40 species to about 60, with 59 accepted. Heinrich Wilhelm Schott named the genus in an 1832 book written with Stephan Endlicher. That understory origin explains the care sheet. A plant built for broken light under a canopy can live in a room, which is how it earned the nickname closet plant and became standard in homes and offices, and why it is rated easy for a beginner and an expert alike.
Bloom time and the flower
Most peace lily cultivars flower only from January to August, and plants grown on for 9 to 15 months usually bloom between February and April, depending on how warm the winter was. Some plants keep no fixed season at all and simply flower freely, and with enough light a few start in early summer and carry on through the year. Indoors an individual bloom may last a month or so, and the white spathe turns pale green after about 10 days and then holds for at least another month. That greening is aging: the spathe pales as the flower gets older and finishes green. The blooms are lightly fragrant, and their shape is close enough to a calla lily that the two are compared constantly.
The reason a peace lily bloomed in the store and never again has little to do with the owner. Researchers at the University of Florida in Apopka found in the early 1980s that a single foliar spray of gibberellic acid makes the plant flower, and growers have used it at 250 parts per million ever since. Flowers appear 70 to 110 days later, and the response does not depend on the time of year or the temperature. Before that, a plant in bloom meant growing it in a large container to mature size, often more than a year of work, and the hormone let growers sell small pots already flowering. The buyer inherits the side effects. Flower size on treated plants is generally smaller, a percentage of the flowers come out distorted, some varieties stretch, and new foliage can come in narrow and strap-shaped. A nursery plant is often flowering below its natural age, so the second bloom waits until it reaches maturity on its own.
Why a peace lily will not bloom
A peace lily that makes leaves and no flowers is nearly always short of light or short of age: lack of flowering usually happens when plants are less than a year old or are growing in insufficient light. It is one of the few foliage plants that will flower in low light at all, but it flowers best in bright indirect light, and most disappointed owners sit in the gap between the two. The foliage stays handsome either way, so nothing signals the problem except the missing flower. Age runs on its own clock: most cultivars, including 'Petite', 'Tys Pride' and 'Viscount', are season and age dependent, flowering only after reaching the age their variety needs, and then only in spring and early summer.
Season, pot and feeding decide the rest. Buds for a spring bloom are set the previous December or January, so a plant that spends winter in a cold dark corner has lost the flower before spring arrives, whatever happens in April. The pot is the quiet cause: peace lily needs a large pot and should be kept somewhat pot-bound, and moving a sulking plant into a much bigger container keeps the mix too wet and brings root rot. Feeding is the lever most often pulled the wrong way. Blooms that open green signal too much nitrogen, and the answer is less fertilizer. A feed sold for flowering carries a higher share of phosphorus, such as 15-30-15, against 20-20-20 for foliage, since phosphorus is what plants draw on for blooming. The timeline is slow either way: fix the light in autumn and the flower, if it comes, arrives the following spring.
Bloom troubleshooting, in order
The first two checks settle most cases, and nothing below them changes anything while the light is wrong.
Varieties worth telling apart
Size is the real choice, because the same white flower sits on plants from 8 inches to 6 feet. Sources split on the top end, giving Sensation as 6 feet tall and wide and also as 4 feet, and on variegation, with 'Domino' called the only variegated peace lily on the market while 'Gemini' carries irregular white stripes of its own.
Light and where to put it
Put a peace lily in bright indirect light, out of direct sun. An east-facing window with morning light, or a north window, comes closest, because that copies the shade it grows in naturally. It prefers partial to deep shade, and it tolerates low light well enough to sit several feet back from an eastern exposure or in a northern one. Low light is survivable; direct sun scorches the foliage. Too much light or heat curls the leaves, burns their margins and tips and leaves the flowering sparse, and the bleached pale color that comes with it is regularly misread as a nutrient deficiency. A well-lighted home interior is often under 100 foot-candles, while a clear sunny day outdoors may exceed 10,000, and commercial crops are grown under 1,500 to 2,500 behind shade cloth, which is a greenhouse figure and no kind of target for a living room. Under fluorescent lamps, 16 hours of light and 8 hours of darkness suit most plants. A thick layer of dust on those wide glossy leaves also inhibits photosynthesis.
Which room that lands in depends on air as much as on light. Dry rooms show on this plant as slow growth, dried-up flower buds and brown leaf tips and edges, so a room that holds its humidity suits it, as long as the light there still clears the low-light floor. Standing several plants together in that spot raises the humidity around all of them, because the collective foliage traps humid air. Two positions are wrong in any room: in the path of a heating or air-conditioning vent, since hot, cold and drafty exposures damage the plant, and pressed against the glass of a winter window, where air of 40 to 60 degrees Fahrenheit slows growth considerably.
Water and the droop
Water thoroughly when the mix has started to dry, and let it dry slightly between waterings. The most accurate gauge is a finger pushed into the mix to the first joint: if the fingertip comes out dry, it needs water. Then water properly, until it runs out of the bottom of the pot, which soaks the lower two thirds where most of the roots sit and washes out excess salts. Empty the saucer afterward, because a plant left standing in water rots at the roots. Use water of 62 to 72 degrees Fahrenheit, left standing overnight so the chlorine evaporates. Softened water is the one to avoid outright, since it adds sodium and chloride to the mix and can damage the plant. If a peat mix has gone very dry and repels water, water once and then again half an hour later.
The droop is the plant's own gauge, and reading it is most of peace lily care. A wilted plant revives after watering, and a severely wilted one resurrects within hours of a thorough soak. That recovery is real, but the habit is expensive: frequent drooping results in brown tips and edges, and soil allowed to dry out excessively turns the leaves and their edges yellow. Not every droop is thirst. In bright light with temperatures above 80 to 85 degrees Fahrenheit, a peace lily may droop in the late day even though the potting mix is moist, and that is normal. Wilting can also come from the opposite cause, because root rot from too much water injures the root system and cuts the plant's ability to take up water, so watering a wilted plant then deepens the damage. Over-watering is the main cause of death of potted plants, and the symptoms of too much and too little resemble each other. Guidance splits on what a droop means: it is read as the plant not receiving enough water, and also as the result of too much. What separates the two is the state of the mix and the roots. For anyone who keeps overshooting from the top, watering from below works very well for peace lilies, which grow well under sub-irrigation.
Soil, pot and repotting
Peace lilies grow in almost any well-drained potting mix, and the best of them are high in organic matter at an acid pH below 6.0. Commercial substrate is built on Canadian peat at 50 to 60 percent by volume, combined with pine bark, vermiculite or coir, which is close to what a bagged houseplant mix already delivers. The pot needs drainage holes, and the mix has to hold moisture in the root zone and let the surplus leave quickly. Repot when roots appear through the drainage holes or circle the top of the soil. Pot size is where the damage gets done, and the advice conflicts: a container just one to two inches larger than the original, because too large a pot keeps the mix too wet and leads to root rot, or a container twice as large as the root ball, typically 6 to 12 inches in diameter. Timing is flexible. Repotting can be done at any time of the year, though the plant recovers quicker if it is repotted during the growing season, and February or March is the usual window.
Temperature and humidity
Peace lilies want ordinary indoor warmth: daytime temperatures between 68 and 85 degrees Fahrenheit with nights about 10 degrees cooler. Most houseplants prefer that daily swing of about 10 to 15 degrees from day to night, and some need it in order to flower. Where the cold floor sits depends on the source, and the spread runs from 40 to 60 degrees Fahrenheit, which in a house means keeping the plant out of an unheated room and off a windowsill on a winter night. Humidity is the least settled part of the care sheet. Most indoor plants come from the tropics and grow best at 40 to 50 percent, while homes fall as low as 10 percent in winter. Peace lily itself is listed both among plants suited to average temperatures and below-average humidity and as a plant that enjoys high humidity. Misting settles neither reading: it cleans foliage, it can spread disease, and it does not raise the humidity around a plant, though a moistened tray of gravel under the pot is recommended for the same purpose.
The numbers where things change
The temperatures and light levels that decide what this plant does.
Feeding
Peace lilies need very little fertilizer, and the damage comes from giving too much. Indoors the fertility need is very low, and because interior plants need less than greenhouse plants the rate is one quarter of the recommended strength, with the soil flushed between applications. Frequency is where sources part company: 20-20-20 at quarter strength every six to eight weeks through spring and summer, or the same fertilizer at 50 parts per million nitrogen once a month, or a balanced feed every 6 weeks from late winter. Organic fertilizer is also recommended, since peace lilies are very sensitive to chemicals. The failure mode is the same whichever schedule you pick: overfertilizing burns the leaf tips and roots and turns them brown, salt buildup damages roots and shows as reduced growth, brown leaf tips, dropping of lower leaves and wilting, and a white film on the soil surface or a white crust on the pot rim says it has already happened. Reduced growth with chlorotic leaves while the soil is cold is a nutrition problem, and winter is when it shows.
Drooping, brown tips, yellow leaves
Five problems produce a similar unhappy plant, and two of them need opposite treatment. Each carries one tell.
What actually goes wrong, most common first
Ordered by how often each turns up in a sample of sixty-eight peace lily threads across Garden.org, Houzz, Dave's Garden and Quora. Root rot is counted inside the decline row, brown tips inside the triage cards above, and Reddit is not in the sample, so the drooping and gnat totals run low.
Thirteen threads, the largest single group, and the phrase that keeps coming back in them is drooping although the soil is moist. Wilting is not proof of thirst, because root rot from too much water cuts the plant's ability to take up water just as dryness does. Feel the mix and check the roots before reaching for the watering can.
Eleven threads titled dying, desperate, or what is wrong with my plant. Root and stem diseases are the most common peace lily problem and they follow over-watering, so the roots and the drainage explain more of these than anything visible on the leaves.
Seven threads, including owners two years past the purchase and one whose twenty-seven-year-old plant had not bloomed for two years. Flowering fails when a plant is less than a year old or is growing in insufficient light.
Seven threads, and most of the photographs show one or two of the oldest leaves at the base, which is the age of the leaf or a plant wanting root room.
Seven threads, nearly all of them reading green as a disease. A spathe that greens late is the flower finishing its run, while blooms that open green on a leafy plant point to too much nitrogen.
Six threads, several from owners who moved a crowded plant into a container four times the size and got sulking in return, because too large a container holds the mix wet enough to rot the roots.
Five threads, most of them starting a week or two after a repot into fresh bagged mix. Peace lilies have few insect pests, but fungus gnats, mealybugs, spider mites and scales all turn up, mealybugs most often of any insect indoors, and beyond those the plant is rated relatively free of pests and diseases.
Propagation by division
Division is the recommended propagation strategy, the plants take to it easily, spring is the season for it, and at home there is no second method. What comes apart are crowns: clusters of leaves, each with its own root system. Slide the plant out of its pot, pull the clump apart with your hands where it wants to separate, cut through the crown with a clean knife where it does not, and leave several leaves on every piece. Each division goes into fresh well-drained mix, in a pot barely bigger than the roots it came with, at the depth it was growing before. Doing this at a repot puts both disturbances into one, and the plant recovers quicker when the work falls in the growing season. Seed belongs to the trade: commercial propagation runs on division, tissue culture and seed germination, with tissue culture now the most common of the three, and exactly one cultivar, 'Cupido', is grown from seed alone in production.
Pruning and cleaning
A peace lily is never pruned in the shrub sense, only tidied. Dead blooms and leaves come off as soon as possible: the spent flower stalk is cut right at the base where it leaves the crown, so no green stub stands in the middle of the plant, and a yellow leaf is taken the same way, at the bottom of its own stalk. Trimming brown portions off with scissors is cosmetic work: it improves appearance, and new browning appears again unless the cause is fixed. The wide glossy leaves collect dust and want a regular wipe with a damp cloth, which also takes off the pests that gather on the underside of the foliage. Leaf shine products are worth skipping, since the waxy residue may interfere with air exchange.
Growing one in water without soil
A peace lily can grow in water alone, and plenty of them are sold that way, standing in a vase with no soil at all. One detail decides how long it lasts. The base of the plant sits above the water line, held up by a vase insert or a layer of small river stones, so the roots grow down into the water while the crown and the leaf bases stay dry, because a base kept constantly wet rots. How often to change the water, and what to feed a plant with no soil holding nutrients for it, have no tested answer, so expect to work both out by trial. Clay pebble setups follow the same rule.
Growing one outdoors
Outdoors, a peace lily is a plant for frost-free ground and nowhere else. The hardiness range is given as zones 11 to 12, and also as zones 10 and 11, a band that on the mainland reaches only the far south. Where the air stays hot and humid the plant does well set straight in the ground. In the rest of the country the pot summers outside and comes back in. Shade is not optional out there, since direct sun scorches the foliage. Time the trip back indoors by the thermometer: growers ship these plants at 55 to 60 degrees Fahrenheit, which makes a sensible floor for a night left outside.
Toxicity, pets, and the air-cleaning claim
Peace lily is toxic to cats and dogs, and the toxic principle is insoluble calcium oxalates. The crystals sit inside the plant cells, and chewing releases them straight into the mouth. The listed signs are oral irritation, intense burning of the mouth, tongue and lips, excessive drooling, vomiting and difficulty swallowing. ASPCA names dogs and cats; horses and children are listed as at risk too, with the vomiting not applying to horses. Poison severity is rated medium, with the leaves named as the poisonous part. All parts of the plant contain calcium oxalate, and eaten in large amounts it can cause stomach or respiratory irritation. The word lily does most of the frightening here, and it is the wrong word for this plant. Peace lily does not contain the toxins found in true lilies, the ones that cause acute kidney failure in cats and some other animals. Calcium oxalate is ordinary equipment in a houseplant collection, shared with philodendrons, daffodils, true lilies and hyacinths, and the response to all of them is the same: stand the plant where an animal cannot get its teeth into it, and pick up the leaf pieces that fall. Where a pet decides what lives in the house, a list of flowers that are safe around cats and dogs is the place to start.
The air-cleaning claim is the plant's best-known selling point and the weakest thing said about it. Peace lily is one of the top selections among air-purifying indoor plants, and NASA praised it in the Clean Air Study for removing formaldehyde, benzene and carbon monoxide from interior air. That work dates to 1989 and was aimed at the air aboard space stations. The method was a potted plant sealed in a chamber of a cubic meter or smaller with one compound injected. Drexel University researchers reviewed a dozen such studies spanning thirty years and found that plants dissipate volatile compounds orders of magnitude slower than the ordinary air exchange of a building. Matching that system, or a couple of open windows, would take between 100 and 1,000 plants per square meter of floor space. Sleeping in a room with one raises no separate question: the documented harm needs the leaves to be eaten.
Meaning, sympathy, and the plant people inherit
The meaning comes from the look of the flower. White spathes rise above the green leaves and are said to resemble white flags of peace, which is where the common name comes from. It holds up in the role: long-lasting flowers on a plant rated easy for a novice and an expert alike, so it survives being given, shipped and left for a week in a hallway. A peace lily that arrives after a funeral needs nothing sentimental, only the brightest indirect corner in the house and water judged by the state of the mix.
Height and spread
Most peace lilies grow 1 to 4 feet tall and about as wide, and a few cultivars reach 6 feet in both directions. Spread here means a crown that thickens as new leaf clusters build, since every leaf rises from the base and nothing runs sideways underground. The recorded spread is 1 to 5 feet, with 3 feet high and wide typical of a plant grown indoors. Final size is decided by the cultivar on the tag: the types bred for interiors run from 12 inches to 4 feet, and Spathiphyllum wallisii tops out around 12 inches.
Myths worth dropping
Five ideas that circulate in comment sections and plant groups, set against what the horticultural record says.
The myth: A cup of sugar water once a week makes it bloom.
The reality: No horticultural source supports it. While a peace lily grows in low light, it flowers best in indirect sunlight.
The myth: It is a lily, so it can kill a cat.
The reality: It carries none of the toxins found in true lilies, which cause acute kidney failure in cats and some other animals. What it does carry is calcium oxalate crystals, and the usual result is burning of the mouth, throat and tongue in a pet or child that chews it.
The myth: A drooping peace lily is dying.
The reality: A severely wilted plant resurrects in a matter of hours from one thorough watering, and the collapse is common enough that the trade has a word for it, crashing.
The myth: A bigger pot is kinder to a crowded plant.
The reality: The plant wants a large pot but should be kept somewhat pot-bound, and the next container up is meant to be one to two inches larger, because too much room keeps the mix wet.
The myth: Tap water is fine for every houseplant.
The reality: Peace lilies are sensitive to chemicals commonly found in tap water, such as fluoride, which may brown the leaf tips over an extended period. Softened water is the worse choice, since it adds sodium and chloride to the mix.
What to expect, year by year
A peace lily runs on the nursery's clock for its first year and on its own after that.
Year one is mostly recovery from the nursery. The blooms it came home with finish on their own schedule, and what follows is a long stretch of leaves. The plant is growing toward the size and age at which it flowers without help, and reaching that size in a large container used to cost a grower more than a year of work. The job in year one is placement and water.
Years two and three are when a home-grown bloom becomes possible. Most cultivars are season and age dependent, flowering only once they reach the age their variety needs and only in spring and early summer. Plants grown on for 9 to 15 months usually bloom between February and April, depending on how warm the winter was.
After that it grows into a clump, and the maintenance shifts to root room. Split the crowns at a repot if it has outgrown its corner, and expect flowering to stay uneven, since long gaps turn up in old, otherwise healthy plants. Final size is set by the variety, from a dwarf holding at 12 to 15 inches to a plant maturing at 6 feet tall and wide.
How long the flower lasts indoors
Peace lily is kept as a flowering houseplant, so the numbers that matter are what the spathe does while it stands in its pot.
Flower photos
FAQ
Where is the best place to put a peace lily in the house?
An east window with morning light, or a north window, since bright indirect light copies the shade it grows in naturally. Favor a room that holds its humidity, because dry air dries up flower buds and browns leaf tips, and keep the pot out of the path of a vent.
How do you care for a peace lily indoors?
Bright indirect light, water when the mix has dried slightly, very little fertilizer, and 68 to 85 degrees Fahrenheit by day with nights about 10 degrees cooler. Wipe the leaves with a damp cloth as dust builds up.
What are the disadvantages of a peace lily?
It is toxic to cats and dogs, carrying insoluble calcium oxalates that burn the mouth. It collapses whenever the mix dries out. In a dim room it keeps its leaves and gives up the flowers, though it is one of the few foliage plants that will flower in low light at all.
Can I sleep with a peace lily in my room?
Yes. The plant is a hazard only to someone who chews it, since all parts contain calcium oxalate and can cause stomach or respiratory irritation when eaten in large amounts.
How do I fix brown tips on a peace lily?
Trim them for looks, and the browning returns until the cause changes: low humidity, too much light, over-fertilizing or low water, and letting the pot dry out too long between waterings.
What does an overwatered peace lily look like?
Wet mix, sparse roots that are sometimes black at the tips, and often a white film on the soil surface.
How do I revive a drooping peace lily?
Feel the mix first. Dry means water thoroughly, and the plant resurrects in a matter of hours; wet means stop, because rotted roots are what stopped it drinking.
Why does my peace lily have leaves but no flowers?
Light and age settle nearly every case: flowering fails when a plant is under a year old or is standing in insufficient light. Most cultivars flower only after reaching the age their variety needs, and then only in spring and early summer.
Why is my peace lily not blooming in winter?
Most cultivars only flower from January to August, so a bare plant in late fall is on schedule. Winter is when a spring bloom is decided, since those buds are set the previous December or January.
Are peace lilies poisonous to cats?
Yes, though not in the way the name suggests: it is not a true lily and does not belong to the family Liliaceae. The insoluble calcium oxalates it carries burn the mouth, tongue and lips of a cat that chews it, with drooling and vomiting to follow.
Interesting tips
- Not every peace lily is the same dark green mound. 'Mojo Lime' is a medium-sized cultivar with lime-green foliage, and 'Power Petite' was bred for dense growth in small containers, which is the one to look for when the shelf space is fixed.
- The plant sold as Cleveland peace lily is a named hybrid, Spathiphyllum x clevelandii, and it turns up with 'Mauna Loa' on the short list of indoor plants for low-light rooms.
- The true flowers are the small bumps covering the cream spadix inside the white sail. They all mature at the same moment, and the spadix sheds pollen for up to four days.
Related Guides & Flowers
Anthurium
The other aroid sold for a colored spathe held above the leaves, and the plant peace lilies are most often mistaken for.
Calla lily
The flower a peace lily bloom is always compared to, grown outdoors in beds and pots.
Lily
The true lilies, the ones carrying the toxin a peace lily does not, and how they are planted and grown.
Flowers safe for cats and dogs
A working list of what an animal can be trusted around when the peace lily has to live out of reach.