Growing Carnivorous Plants as Houseplants — Seattle’s Favorite Garden Store Since 1924 – Swansons Nursery

Flytrap / Dionaea muscipula

Arguably the most iconic carnivorous plant, the flytrap is the only species within the genus Dionaea, D. muscipula. It has inspired a magnificent array of unforgettable works in popular culture, from the singing, man-eating monstrosity in The Little Shop of Horrors to the deadly piranha plant of the Super Mario Bros. media franchise.

The flytrap is native to bogs and wetlands of coastal North and South Carolina. Like other carnivorous plants, D. muscipula prefers peaty, sandy soils that are low in nitrogen and phosphorus. It produces a tall scape with delicate white flowers in early spring. Natural wildfires in the plants’ wild habitat help to keep D. muscipula from being shaded out by taller grasses and shrubs, and ash acts as a fertile substrate for seeds to germinate in newly-burned areas. While it is common in the houseplant market, D. muscipula is classified as vulnerable to extinction in the wild due to illegal poaching, habitat loss, fire suppression, and sea level rise.

The mechanism for carnivory in D. muscipula is perhaps the most fascinating among carnivorous plants, if not the most dramatic to witness. The modified leaves form a pair of flat lobes ringed with hair-like protrusions, giving the impression of toothy maws. Like its sundew cousins in the genus Drosera, Dionaea leaves deploy red pigmentation and secrete mucilage to help attract insect prey. However, its trapping mechanism goes a step further. Tiny “trigger hairs” on the inside of the leaves send signals to the plant when they are stimulated. An isolated brush will not trip the trap–a piece of windblown debris or minuscule gnat is not worth the effort of closing the trap. If multiple trigger hairs are stimulated in succession–indicating a meal-worthy insect is present in the trap–the leaf will snap shut in the blink of an eye. The toothlike hairs ringing the trap prevent the victim from escaping, and as the prey struggles against the trigger hairs within the trap, the edges of the maw purse together to form a tight seal. As the victim suffocates, the plant pumps digestive enzymes into the trap. Once all available nutrients are absorbed, the trap reopens to reveal a husk of chitin, which usually falls or blows out of the trap to clear it for reuse. While the plants themselves are not fireproof, the trigger hairs of Dionaea are also heat-sensitive, closing in proximity to fire to help the plant avoid excessive damage.

As a houseplant, the flytrap is quite easy to care for since it tolerates lower levels of humidity compared to other carnivorous plants. Give it direct sunlight in an unobstructed south- or west-facing window, using a potting mix composed of approximately 60% horticultural sand and 40% sphagnum moss. Keep a quarter-inch of mineral-free water in its cache pot or tray at all times, and avoid pouring water directly on the traps. While triggering empty traps to close can be fun to watch, this is a waste of energy for the plant and weakens it over time. If you’d like to witness its insect-trapping abilities, use tweezers to place a housefly-sized insect in the trap so the plant gets a meal for its efforts. Gently clear stuck husks from reopened traps to maximize the plant’s ability to catch more insects.

While their care varies slightly from other houseplants, carnivorous plants are relatively easy to grow if given lots of light, proper soil, and mineral-free water. Their unique insect-trapping abilities bring equal parts entertainment and utility to a sunny windowsill, and varieties like S. purpurea give us the rare opportunity to grow a native plant inside our homes. On your next visit to the nursery, allow yourself to be captivated by your favorite carnivorous plant, and give it a try!

Other Resources

Swansons’ quick guide to carnivorous plant care guide

International Carnivorous Plant Society (facts, care, propagation, conservation, and more)