Fungus gnats are those tiny black flies that hover around your houseplants and drift up every time you water. They're harmless to people, but they sure are annoying. The good news is that some carnivorous plants, like sundews, rainbow plants (Byblis) and butterworts, are excellent at catching them. Here are the best ones for the job, plus a few simple tips to help you get gnats under control.
How carnivorous plants catch fungus gnats
The best gnat catchers are "flypaper" plants. Their leaves are covered in sticky droplets that look like dew. A gnat lands for a sip, gets stuck, and the plant slowly digests it. Because fungus gnats are so small and weak, they're the perfect prey for sticky plants.
Snap traps like Venus flytraps are amazing, but they're built for bigger bugs. A gnat is usually too small to set off the trap. For gnats, sticky plants win.
1. Cape sundew (Drosera capensis)
The Cape sundew is one of the easiest carnivorous plants you can grow, and it's a gnat-catching machine. Its long, strap-shaped leaves are lined with sticky tentacles, and the leaves slowly curl around whatever they catch. It's fun to watch.
Try Drosera capensis (Typical) for a classic, easy grower, or Drosera capensis 'Dark Maroon Red' for deep red color.
2. Spoon-leaf sundew (Drosera spatulata)
Drosera spatulata forms a small, flat rosette of spoon-shaped leaves that sparkle with dew. It stays compact, so it fits nicely on a windowsill or tucked in next to your other houseplants. Its low rosette sits right where fungus gnats like to hang out, near the soil.
3. Rainbow plants (Byblis)
Rainbow plants are one of our favorite gnat catchers, and they're very good at capturing prey. Their slender leaves are covered in sticky droplets that sparkle in the light. Byblis get much larger than sundews and put on a lot more of their beautiful pink flowers. They're also more tolerant of lower light than sundews, which makes them a great choice for beginners.
Byblis are annuals in nature (except Byblis gigantea), but indoors under grow lights they can be grown year after year.
- Byblis filifolia: grows tall with pink flowers, and its thicker stem keeps it growing upright even in lower light
- Byblis guehoi: grows tall with pink flowers, and can sprawl or vine in lower light
- Byblis liniflora: a medium-height grower that stays shorter with even more flowers, and is self-fertile, so it often drops seeds
4. Mexican butterworts (Pinguicula)
Butterworts are some of the best gnat catchers out there. Their flat leaves feel a little greasy, and they're coated in a fine sticky film that grabs gnats on contact. Many growers keep a butterwort in every room for exactly this reason. They come in lots of shapes and colors, too.
A few favorites:
- Pinguicula gypsicola x sethos: a vigorous grower with green leaves and translucent pink tips
- Pinguicula 'Estrellita': a pretty pink shade with curled, spade-shaped leaves
- Pinguicula moranensis x agnata: lovely purplish coloration
- Pinguicula 'Snow Queen': green leaves with white edges
- Pinguicula ehlersiae 'Cotton Candy': cupped leaves with a light pink hue
In winter, most Mexican butterworts go into a hibernation phase. They grow smaller, more succulent-like leaves, and you can keep the soil a little less wet until normal leaves return in spring. This is normal.
Easy care for gnat-catching plants
- Light: Give them bright light, like a sunny window or a grow light. Sundews show their best color and dew in good light. Byblis handle lower light better than sundews.
- Water: Use only distilled, rain, or reverse osmosis (RO) water. Tap water has minerals that build up and harm the roots. Sundews and Byblis like to sit in a shallow tray of water. Butterworts like their soil lightly moist, not soggy.
- Soil: Sundews grow well in peat and perlite, and Byblis in a peat-based mix. Butterworts prefer a gritty, well-draining mix.
- Temperature: Keep them above 40°F. Sundews and butterworts grow indoors year-round with no winter dormancy needed. Give Byblis warmth and 14 to 16 hours of grow light to keep them growing year after year.
Don't worry about feeding them. They'll catch plenty on their own.
Tips to get fungus gnats under control
Carnivorous plants are a great helper, but they work best as part of a team. Fungus gnats lay their eggs in damp potting soil, so a few simple habits make a big difference:
- Let the top of your regular houseplants' soil dry out between waterings. Gnats love constantly wet soil.
- Don't leave standing water in your regular houseplants' saucers.
- Place your sundews, rainbow plants and butterworts right next to the plants where you see the most gnats.
- Be patient. Your plants will keep catching new adults as they hatch, which helps break the cycle over time.
Shop gnat-catching plants
We put our favorite gnat catchers together in one place: browse the Carnivorous Plants for Fungus Gnats collection. Every plant ships potted and ready to grow. During cold months, add a shipping heat pack to help protect your plant in transit. For more growing tips, see our Sundew Care Guide , Rainbow Plant Care Guide and Butterwort Care Guide.
Fungus gnat FAQ
What is the best carnivorous plant for fungus gnats?
Rainbow plants (Byblis), Mexican butterworts (Pinguicula) and sundews like Drosera capensis and Drosera spatulata are among the best. Their sticky leaves catch gnats easily, and they're simple to grow indoors. Byblis are especially good at capturing prey, and they grow larger and flower more than sundews.
Will a carnivorous plant get rid of all my fungus gnats?
They catch a lot of them, but they work best alongside good habits, like letting your houseplants' soil dry out on top between waterings. Together, they help break the gnat life cycle.
Can a Venus flytrap catch fungus gnats?
Not very well. Gnats are usually too small to trigger a flytrap's trap. Sticky plants like sundews, rainbow plants and butterworts are much better at catching them.
Do sundews, butterworts and rainbow plants need a winter dormancy?
No. The sundews and Mexican butterworts in our gnat collection grow indoors year-round. Butterworts may form smaller, succulent-like winter leaves, which is a normal hibernation phase. Rainbow plants are annuals in nature (except Byblis gigantea), but indoors under 14 to 16 hours of grow light they can be grown year after year.