Houseplant · Lentibulariaceae
Butterwort
Pinguicula moranensis
Give it bright light, rainwater, and a lean gritty mix, and the butterwort happily clears your gnats for free.
Bright indirect
Every 2–5 days
41–86°F · 5–30°C
USDA 10–11
Overview
Here's a carnivorous houseplant that hunts with glue instead of snapping jaws. Its flat rosette of greasy, sticky leaves grabs fungus gnats and small flies, then digests them for the nutrients its lean soil just can't offer. This Mexican one, Pinguicula moranensis, comes from volcanic country, and it's perfectly happy sitting on a bright windowsill.
The fun part? It basically wears two outfits over the year. Spring through autumn it spreads out wide, glistening carnivorous leaves and sends up slender stalks of pink-violet flowers. Then as the days get shorter, it tucks itself into a tight, non-sticky succulent rosette and waits out winter on almost no water.
What throws people off isn't that it's hard, it's that it's backwards. Butterworts want the exact opposite of normal houseplant care: no fertilizer, no tap water, and no rich potting mix. Get those three sorted and the plant pretty much takes care of itself.
Care
The short version: bright light, only distilled or rainwater, and a lean gritty mineral mix. Keep it evenly damp while it's growing, let it dry out for the winter rosette, and don't ever feed the soil.
Light
Butterworts love bright light, ideally bright indirect with a few hours of sun thrown in. They'll take anything from full sun to partial shade, but leaves grown too dim go pale and quit making their sticky dew, so don't tuck it in a dark corner.
Water
Stick to distilled, reverse-osmosis, or rainwater, never tap, because the minerals build up and end up killing the plant. Keep the gritty mix evenly damp while it's growing, which is easiest if you just sit the pot in a shallow water tray. Come its winter rosette, it wants way less, just a light drink when the mix nearly dries.
Soil
Pot it in a gritty, low-nutrient mineral mix, think peat or long-fiber sphagnum cut with sharp sand, perlite, and a bit of pumice. Any pH from 5.0 to 7.0 is fine. Skip rich potting soil completely, since the roots are built for lean ground.
Temperature
This Mexican species is pretty laid-back about temperature, happy anywhere from about 41°F to 86°F (5°C to 30°C). That wide range means it shrugs off the usual household ups and downs, as long as it never actually freezes.
Humidity
Despite the whole carnivore thing, it really doesn't need a terrarium. Average household humidity of 40% to 60% suits it just fine, and honestly, good airflow matters way more than chasing some high number.
Feeding
Don't bother feeding the soil at all. The plant feeds itself by catching fungus gnats and small flies on its leaves, and tossing feed in the pot just burns the roots.
Pruning
There's no shaping to do, thankfully. Just pick off any dead, blackened, or rotted leaves and spent flower stalks every so often, which keeps fungal rot from getting started.
Repotting
Repot it every 1 to 2 years, best in spring when growth kicks back in. 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
It's a little thing, only 2 to 10 inches (5 to 25 cm) tall and spreading 3 to 6 inches (8 to 15 cm) across. One rosette fits comfortably in a modest pot on a windowsill.
Troubleshooting
Just about every butterwort problem traces back to water, feeding, or the seasons, so it's rarely a mystery. Match what you're seeing to the list below before you do anything, because the natural reaction, like more water or a bit of fertilizer, usually just makes it worse.
Blackened, mushy crown that collapses
So the crown's gone black and squishy? That's crown rot, and it nearly always comes down to water. Tap or mineral water leaves salts sitting in the lean mix, and a soggy pot through the winter rosette phase finishes the job. Swap to distilled or rainwater, rinse the mix through, repot into fresh gritty stuff, and snip off anything soft and brown.
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
Fresh leaves coming in dry and dull instead of glistening? The plant's usually unhappy about mineral buildup or feeding. Fertilizer and rich soil burn the roots, tap water packs the mix with salts, and weak light just makes everything sluggish. Don't feed the soil, flush it with distilled or rainwater, and shift 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
No need to panic over this one, because it's just the winter succulent phase. When the days get shorter, the plant trades its sticky carnivorous leaves for a tight little non-sticky rosette and coasts through the cold. Back off the water until the mix nearly dries, keep it in bright light, and things go back to normal in spring.
Fix:
- Reduce watering and let the mix nearly dry
- Keep in bright light and resume normal moisture in spring
Toxicity
Good news if you've got animals at home: the butterwort is not toxic to pets or people. The sticky leaves only catch gnat-sized bugs and carry nothing harmful, so the real reason to keep it out of reach is just to save that delicate rosette from curious paws.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
If a nosy cat licks or bats the sticky leaves, all it gets is a tacky tongue. There's no toxin in there to worry about.
Dogs None
Dogs are totally fine with this one. There's no poison anywhere in it, so a chewed leaf just tastes a bit greasy.
Horses Safe
Horses have nothing to fear, though let's be honest, that tiny rosette wouldn't stand a chance against a grazing muzzle.
Rabbits Safe
Rabbits are safe here. A nibbled leaf won't bother the bunny one bit, even if it sets the plant back.
Livestock Safe
Cattle, goats, and sheep are all in the clear. There's nothing toxic in it, and a tray-grown houseplant hardly ever crosses their path anyway.
Birds Safe
Birds won't run into any chemical trouble from the leaves or flowers. That sticky stuff only grabs gnat-sized bugs, nothing bigger.
People Safe
You can pick it up bare-handed no problem, since the leaf just feels greasy. It's not a food plant either, so there's nothing on it meant for eating.
The greasy, sticky leaf surface is harmless to handle and to pets; it simply feels tacky.
Varieties
Most people run into the butterwort as one of a few common forms. These are the ones you're most likely to spot by name.
Pinguicula moranensis
The classic big-flowered Mexican butterwort, with pink-violet blooms perched above a flat summer rosette of greasy leaves.
Pinguicula moranensis var. neovolcanica
A recognized variety out of the Mexican volcanic ranges, accepted on Kew's Plants of the World Online.
Pinguicula 'Tina'
A vigorous hybrid that's a great easy, gnat-catching houseplant if you're just getting into these.
How to propagate
Butterworts are easy to make more of, and the simplest way costs you nothing but a few leaves off a plant you've already got.
Leaf cuttingsEasy
Late winter to spring, especially from the succulent winter rosette · 4-8 weeks to form plantlets
Want more butterworts? Leaf pulling is the easiest trick going. In late winter or spring, while the plant's in its succulent rosette, gently tug whole leaves off the base and lay them on damp gritty mix. Little new rosettes pop up at the leaf base in about 4 to 8 weeks.
DivisionEasy
Spring at repotting · 2-4 weeks
Older plants often pump out offset rosettes around the parent, which makes things easy. When you repot in spring, just split those clusters apart and pot each one up on its own, and they'll settle in within 2 to 4 weeks.
SeedDemanding
Spring on the surface of damp mineral mix · Several months to a year
Seed's the slow lane, no two ways about it. Scatter the fine seed on the surface of damp mineral mix in spring and just wait, because it can take several months to a year to bulk up. It's fussier than leaf pulling, but it's the way to go when you want loads of plants at once.
Myths
You have to hand-feed butterworts insects or fertilize them to keep them alive.
Nope, the sticky leaves catch their own fungus gnats and small flies, and honestly that's all the feeding the plant wants. Never fertilize the soil, because the roots are made for lean ground and extra nutrients just burn them.
Butterworts are toxic to cats and dogs.
Not the case at all. Pinguicula isn't on the ASPCA toxic plant list and counts as non-toxic to pets. The leaves only catch tiny insects and carry nothing that'd hurt a curious animal.
Every carnivorous plant needs a sealed, humid terrarium.
Not this one. Mexican butterworts do just fine in ordinary household humidity as long as they get low-mineral water and bright light. A sealed case can actually backfire, trapping stale air that's perfect for rot.