Peace Lily (Spathiphyllum)

Peace Lily, Spathe Flower, White Sails

With the graceful common name “peace lily”, Spathiphyllum is an easy care, low light houseplant. It also removes many toxins from indoor air including formaldehyde and ammonia.

I. Appearance and Characteristics 

Spathiphyllum is a genus of about 47 species of monocotyledonous flowering plants in the family Araceae, native to tropical regions of the Americas and southeastern Asia. Certain species of Spathiphyllum are commonly known as spath or peace lilies.

They are evergreen herbaceous perennial plants with large leaves 12–65 cm long and 3–25 cm broad. The flowers are produced in a spadix, surrounded by a 10–30 cm long, white, yellowish, or greenish spathe. The plant does not need large amounts of light or water to survive. They are most often grown as houseplants, however they are able to withstand the elements well enough to thrive when planted outdoors in situations that are hot and humid.

Schott’s description of the genus refers to Spatha foliaris persistens, where spatha is a spathe, and foliaris is an adjective modifying spathe, meaning relating to a leaf, and persistens means continuing or persisting. Phyllum also means a leaf. The more common name of peace lily derives from the plant’s symbolism for peace, purity, and healing, and has also been associated with the white flag, which is a signal for truce.

Toxicity

Although it is called a “lily”, the peace lily is not a true lily from the family Liliaceae. True lilies are highly toxic (poisonous) to cats and dogs, but the peace lily, spathiphyllum, is only mildly toxic to humans and other animals when ingested. Like many Araceae it contains calcium oxalate crystals, which can cause skin irritation, a burning sensation in the mouth, difficulty swallowing, and nausea, but it does not contain the toxins found in true lilies, which could cause acute kidney failure in cats and some other animals.

II. How to Grow and Care

Sunlight

A peace lily needs sunlight, though not direct sun. They are shade-loving plants in their native habitats. But peace lilies indoors need a bit more filtered light. (Some varieties can withstand more light than others.) An east-facing window is a prime spot to place a peace lily in your house.

Temperature and Humidity

These plants prefer moist warmth. Avoid cold drafts and temperatures that fall below 55 degrees Fahrenheit; the plant will die when exposed to prolonged cold temperatures. The ideal temperature range for your peace lily is 65 to 80 degrees Fahrenheit. Spritz the leaves every week with softened or distilled water throughout the summer growing season to raise humidity.

Watering

Peace lilies prefer being under-watered rather than overwatered. How often you should water a peace lily depends on container size and how fast the soil drains, but, in general, water when the top inch of soil has dried out. In winter, reduce watering but never allow the soil to dry out completely. If your water at home is highly chlorinated, it’s a good idea to use filtered or distilled water. Alternatively, you can allow tap water to sit for several days until the chlorine evaporates.

Soil

Peace lilies like a rich, loose potting mix that contains plenty of organic matter. These plants are native to tropical canopy conditions where the soil is packed with deteriorating plant material, so you’ll find the best success with soil that mimics this composition. Additionally, the plant is also very sensitive to too-damp soil conditions, so be sure to choose a well-draining mixture.

Fertilizing

Peace lilies appreciate frequent feedings, which result in the strongest plant and seasonal blooming. Following manufacturer’s instructions, feed your plant weekly in the summer or use slow-release pellets at the beginning of the season. You do not need to fertilize the plant during the winter.

Planting Instructions

Peace lilies are happiest when they’re somewhat root-bound. However, when the plant has clearly exceeded the capacity of the pot, it can be potted up to a larger container in the early spring. If you notice roots popping up out of the soil and down from the drainage holes, it’s time to repot. It’s ideal to pot the plant in a terracotta or clay vessel that can wick away excess moisture. Always use a high-quality potting mix, and a pot with good drainage.

Propagation

The peace lily is generally propagated by dividing clumps during repotting activities, which can be done during any season. Inspect the plant for small offshoot crowns located adjacent to the main parent plant; this is a sign the plant is ready to divide. Here’s how:

  • Remove the entire plant from its container, and then tug apart or cut away the adjacent crowns. You can also simply cut away a section of the main root ball. Any piece that has two or more leaves and attached roots will likely grow successfully.
  • Fill a 6-inch pot with a fresh potting mix that is moist but not soggy.
  • Immediately plant the clumps in the container, and water thoroughly.
  • Keep the plant somewhere warm and well-lit. The roots should reestablish themselves in less than a month.

Repotting

Repot your peace lily in spring if the roots begin to reach through the holes at the bottom of the plastic nursery pot. Choose another plastic pot 1-2 sizes bigger (about 2-5cm) to give her room to grow. Peace lilies can be split into multiple plants by dividing the clump, making sure each new plant has some good strong roots to grow from. Peace lily may take some time to adjust to her new home, so don’t panic if she stops flowering for a while.

Pests and Diseases

Common Pests

These plants are free of most diseases and pests that can plague houseplants. But they can be susceptible to scale and mealybugs. Spot treatment with horticultural oil is a good strategy for these pests.

Common Problems 

Under the right growing conditions, peace lilies typically thrive without issues. But some problems can arise if the environment isn’t quite right.

Curling Leaves

Curled, pale leaves generally indicate that the plant is receiving too much light overall. And scorched leaves indicate too much direct sun. In either case, the plant should be moved to a shadier location.

Plant never flowers

Check that the plant is receiving enough light, water, and occasional fertilizer, and is slightly root bound in the pot.

Plant is constantly droopy

If it doesn’t perk back up after being watered, it may have a root disease from being over-watered. Repot in fresh soil and a clean new pot, removing all black/damaged roots. Be careful with watering after repotting.

Leaf tips are brown

You might notice browning on your peace lily’s leaf tips. This can be due to too much or too little water, as well as poor soil drainage. It also can arise due to insufficient humidity. Plus, the buildup of salts in the soil might be a culprit. Ensure that your plant is properly watered and that the soil is draining. If that doesn’t seem to be the issue, try flushing the soil by watering until you see water coming from the drainage holes to remove the salts.

III. Types of Peace Lilies

Peace lilies have been heavily hybridized and therefore come in dozens of popular varieties. They range in size from miniature to massive and from deep green with snow-white flowers to golden-leaved beauties. Some of the popular types of peace lilies include:

  • ​Spathiphyllum ’Power Petite’: A small varietal that grows to only about 15 inches
  • S. ‘Mauna Loa Supreme’: A very common variety that grows to be between 3 to 4 feet tall, with leaves that are up to 9 inches wide
  • S. ‘Sensation’: The largest peace lily varietal, which reaches up to 6 feet in height with broad, 20-inch long leaves
  • S. ‘Mojo’: A striking, large varietal with vibrant green leaves
  • S. ‘Golden Delicious’: A varietal that features new growth with stunning golden-green color
  • S. ‘Starlight’: A varietal with narrow leaves that have wavy margins. It’s also known for having multiple blooms, with as many as 20 flowers on a single plant

IV. How to Get Peace Lily to Bloom

Peace lilies are notoriously difficult when it comes to blooming. Sometimes even the happiest, healthiest plants don’t bloom outside of their natural rainforest environment. If you’re hoping to have your indoor peace lily bloom, your best bet is to provide it with very consistent ideal conditions, especially when it comes to humidity, diffused light, and consistent fertilizer.

The peace lily flower stages are budding, blooming, going to seed, and wilting. The buds are fairly small and unfurl like leaves. It can take some time for them to come into bloom, so be patient. When the bloom fades, deadhead the spend flower. In optimum conditions, the plant will flower twice a year in spring and fall.

V. Uses and Benefits 

Several species are popular indoor houseplants. It lives best in shade and needs little sunlight to thrive, and is watered approximately once a week. The soil is best left moist but only needs watering if the soil is dry. The NASA Clean Air Study found that Spathiphyllum cleans certain gaseous environmental contaminants, including benzene and formaldehyde. However, subsequent tests have shown this cleaning effect is far too small to be practical.

The cultivar ‘Mauna Loa’ has won the Royal Horticultural Society’s Award of Garden Merit.

Peace Lily (Spathiphyllum) Details

Common name Peace Lily, Spathe Flower, White Sails
Botanical name Spathiphyllum
Plant type Herb
Hardiness zone 11a, 11b, 12a, 12b
Height 1 ft. 0 in. - 6 ft. 0 in.
Width 1 ft. 0 in. - 6 ft. 0 in.
Sunlight Deep shade (Less than 2 hours to no direct sunlight)
Soil condition High Organic Matter
Flower color Cream/Tan
Leaf color Green