Houseplant · Lentibulariaceae
Butterwort
Pinguicula moranensis
Give it bright light, rainwater, and a lean gritty mix, and the butterwort clears your gnats for free.
Bright indirect
Every 2–5 days
41–86°F · 5–30°C
USDA 10–11
Overview
The butterwort is a carnivorous houseplant that hunts with glue instead of snapping jaws. Its flat rosette of greasy, sticky leaves catches fungus gnats and small flies, then digests them for the nutrients its lean home soil can't provide. This Mexican species, Pinguicula moranensis, comes from volcanic country and grows happily on a bright windowsill.
Two looks share the same plant across the year. From spring to autumn it spreads wide, glistening carnivorous leaves and sends up slender stalks of pink-violet flowers. As the days shorten, it pulls back into a tight, non-sticky succulent rosette and waits out winter on barely any water.
What trips up most growers isn't difficulty, it's habit. Butterworts want the opposite of normal houseplant care: no fertilizer, no tap water, and no rich potting mix. Get those three right and the plant practically looks after itself.
Care
The short version: bright light, only distilled or rainwater, and a lean gritty mineral mix. Keep it evenly damp through the growing season, let it dry out for its winter rosette, and never feed the soil.
Light
Butterworts want bright light, ideally bright indirect with a few hours of sun. They tolerate full sun through to partial shade, but leaves grown too dim turn pale and stop making their sticky dew.
Water
Use only distilled, reverse-osmosis, or rainwater, never tap, since dissolved minerals build up and kill the plant. Keep the gritty mix evenly damp through the growing season, often by standing the pot in a shallow water tray. In its winter rosette the plant wants far less, watered lightly only when the medium nearly dries.
Soil
Plant in a gritty, low-nutrient mineral mix, something like peat or long-fiber sphagnum cut with sharp sand, perlite, and a little pumice. A pH anywhere from 5.0 to 7.0 works. Skip rich potting soil entirely, because the roots are built for lean ground.
Temperature
This Mexican species is comfortable across a wide range, from about 41°F to 86°F (5°C to 30°C). That span makes it forgiving of ordinary household swings as long as it never freezes.
Humidity
Despite the carnivorous reputation, it doesn't need a terrarium. Average household humidity of 40% to 60% suits it fine, and good airflow matters more than chasing a high number.
Feeding
Don't fertilize the soil at all. The plant feeds itself by catching fungus gnats and small flies on its leaves, and adding feed to the pot only burns the roots.
Pruning
There's no shaping to do. Just pick off dead, blackened, or rotted leaves and spent flower stalks now and then, which keeps fungal rot from getting a foothold.
Repotting
Repot every 1 to 2 years, best done in spring as growth resumes. Move it on when the mix breaks down and stays soggy, when the rosette crowds the pot edge, or when new leaves stop turning sticky.
Size & spacing
This is a small plant, reaching only 2 to 10 inches (5 to 25 cm) tall and spreading 3 to 6 inches (8 to 15 cm) across. A single rosette fits comfortably in a modest pot on a windowsill.
Troubleshooting
Nearly every butterwort problem comes back to water, feeding, or the seasons. Read the signs against the list below before you reach for a fix, because the wrong response, like more water or fertilizer, usually makes things worse.
Blackened, mushy crown that collapses
This is crown rot, and it almost always traces back to water. Tap or mineral water leaves salts behind in the lean mix, and a soggy pot during the winter rosette phase pushes the crown over the edge. Switch to distilled or rainwater, flush the medium, repot into fresh gritty mix, and cut away any soft brown tissue.
Fix:
- Stop watering until the mix is barely moist
- Flush the medium with distilled/RO water to leach salts
- Repot into fresh gritty mineral mix and remove rotted tissue
- Increase airflow and light
New leaves lose their sticky dew
When fresh leaves come in dry and dull, the plant is usually reacting to mineral buildup or feeding. Fertilizer and rich soil burn the roots, tap water loads the mix with salts, and weak light slows everything down. Never feed the soil, flush with distilled or rainwater, and move the plant somewhere with several hours of bright light.
Fix:
- Never fertilize the soil
- Switch to distilled/RO/rain water and flush the mix
- Move to a brighter spot with several hours of bright light
Leaves shrink into small succulent rosettes in autumn
This is the winter succulent phase, not a problem at all. As the days shorten, the plant trades its sticky carnivorous leaves for a tight, non-sticky rosette and rides out the cold months. Ease off the water until the mix nearly dries, keep it in bright light, and let normal moisture resume in spring.
Fix:
- Reduce watering and let the mix nearly dry
- Keep in bright light and resume normal moisture in spring
Toxicity
Good news for households with animals: the butterwort is not toxic to pets or people. The sticky leaves trap only gnat-sized insects and carry nothing harmful, so the main reason to keep it out of reach is to protect the fragile rosette from curious paws.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
A curious cat can lick or paw the sticky leaves with nothing worse than a tacky tongue. There is no toxin here to worry about.
Dogs None
Dogs are in the clear. The plant carries no poison, and the worst a chewed leaf does is leave a greasy taste.
Horses Safe
Safe to be around horses, though the small rosette is far too delicate to survive a grazing muzzle.
Rabbits Safe
Harmless to rabbits. A nibbled leaf won't hurt the animal, even if it costs the plant.
Livestock Safe
No risk to cattle, goats, or sheep. The plant holds nothing toxic, and as a tray-grown houseplant it rarely meets them anyway.
Birds Safe
Birds face no chemical hazard from the leaves or flowers. The sticky surface only traps gnat-sized insects, not anything larger.
People Safe
Safe to handle bare-handed; the leaf just feels greasy. It is not a food plant, so there is no part meant for eating.
The greasy, sticky leaf surface is harmless to handle and to pets; it simply feels tacky.
Varieties
Most growers meet the butterwort through one of a few common forms. These are the ones you're most likely to find by name.
Pinguicula moranensis
The classic large-flowered Mexican butterwort, carrying pink-violet blooms above a flat summer rosette of greasy leaves.
Pinguicula moranensis var. neovolcanica
A recognized variety from the Mexican volcanic ranges, accepted on Kew's Plants of the World Online.
Pinguicula 'Tina'
A vigorous hybrid prized as an easy, gnat-catching houseplant for beginners.
How to propagate
Butterworts are easy to multiply, and the simplest method costs you nothing but a few leaves from a plant you already own.
Leaf cuttingsEasy
Late winter to spring, especially from the succulent winter rosette · 4-8 weeks to form plantlets
The easiest way to multiply a butterwort is by leaf pulling. Gently tug whole leaves from the base in late winter or spring, when the plant is in its succulent rosette, and lay them on damp gritty mix. New rosettes form at the leaf base within 4 to 8 weeks.
DivisionEasy
Spring at repotting · 2-4 weeks
Mature plants often throw offset rosettes around the parent. At spring repotting, separate these clusters and pot each one on its own, and they settle in within 2 to 4 weeks.
SeedDemanding
Spring on the surface of damp mineral mix · Several months to a year
Seed is the slow road. Surface-sow the fine seed on damp mineral mix in spring and wait, because it can take several months to a year to size up. It's less reliable than leaf pullings but worthwhile when you want many plants at once.
Myths
You have to hand-feed butterworts insects or fertilize them to keep them alive.
The sticky leaves catch their own fungus gnats and small flies, and that is all the feeding the plant needs. Never fertilize the soil, since the roots are built for lean ground and added nutrients burn them.
Butterworts are toxic to cats and dogs.
Pinguicula isn't on the ASPCA toxic plant list and is treated as non-toxic to pets. The leaves trap only tiny insects and carry nothing that would harm a curious animal.
Every carnivorous plant needs a sealed, humid terrarium.
Mexican butterworts do fine in ordinary household humidity as long as they get low-mineral water and bright light. A sealed case often does more harm than good by trapping stale, rot-friendly air.