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If the idea of carnivorous plants makes you immediately think of the bloodthirsty man-eater in Little Shop of Horrors, you’re not alone! Carnivorous plants (such as the Venus flytrap) dine only on insects—not humans! Here are three fun carnivorous houseplants.
Yes, they eat those pesky little bugs! The speed at which they can snap shut on their prey is amazing. No, they don’t eat people or pets, though some larger tropical ones may be able to catch a wayward mouse, frog, or lizard.
Carnivorous plants are not only fascinating because of their bizarre way of feeding themselves, but they’re also have some unusual and beautiful forms.
Most plants (that aren’t carnivorous) get nutrients by absorbing nitrogen from the soil through their roots. But carnivorous plants grow in low-nutrient environments such as bogs and fens. To find nutrients in poor soils, these plants have evolved to get their nutrients from whatever they can catch.
The methods of entrapment vary by species of plant, such as pitfall traps, snap traps, suction traps, and flypaper. Their plants use fragrance, false flowers, nectar and other ploys to lure their insects, then produce digestive fluids to absorb the insects and their nutrients.
We’ll discuss a few of the common carnivorous houseplants.
1. Venus Flytrap
The most famous of the carnivorous plants is the Venus Flytrap (Dionaea muscipula). It’s a “snap trap.” Unlike Audrey in Little Shop of Horrors, these ground-hugging plants are quite small—only a few inches across with pairs of one-inch long hinged leaves that can snap like a trap, similar to our jaws. Yes, they’re small but they are effective at catching small prey!
Insects are lured into the trap by its sweet nectar and inadvertently brush against the trigger hairs. Nothing happens after the first touch but the trap snaps shut the second time the hairs are touched. Fine teeth along the edge of the leaves keep the victim locked in place. As the captured bug struggles, the trap closes even tighter. The plant then exudes a digestive enzyme to dissolve its victim so it can absorb its nutrients. After successfully sucking up 3 or 4 bugs the leaves will die off and new traps will grow.
Why does it take two or more touches of the hairs being touched by the insect? This prevents the trap from being set off by a simple raindrop. However, the trap can only snap about seven times before the leaves die off, so don’t keep playing with your plant or it will slowly die!
Native to bogs in the Carolinas where they are considered endangered, Venus Flytraps are a fun houseplant that most kids find fascinating. Though it is often said that you can feed your housebound flytrap bits of hamburger, it is not recommended since it could rot the traps. Indoors, you’ll need to give them bugs to eat. A couple of houseflies or small slugs each month are ample. Don’t overfeed them. They are slow eaters and it takes several weeks for them to fully digest an insect.
Since they are bog plants, they like having wet feet so sit the pot in an inch of water in a tray or saucer. Use only distilled or rain water since minerals can harm them. They also like bright light and will make larger traps if given 3 to 6 hours of full sun a day. Put your flytraps outside during a buggy spring and summer and the busy plants can grow a new trap a week. They never need fertilizing since they catch their own food. In fall and winter they go dormant. Place them out of direct sun in a bright chilly location for 2 to 4 months while they rest and keep them barely moist. Repot in March when new growth starts and return them to sun and warmth. They have small white flowers but it is recommended not to let them blossom because it weakens the plant.
Pitcher Plants are called “pitfall trappers.” Their large leaves look like tall water pitchers and are filled with water and a digestive fluid that accumulate in the base of the plant. They attract their prey with pretty “false” flowers and the promise of sweet nectar. Flies, ants, and other small bugs are lured to their funnel-like leaves and which are slippery inside, and the bugs accidentally slide down into the pool of digestive fluid. Downward facing hairs prevent the captured bugs from climbing back out and here they drown and decompose to feed the plant. The insects that decay in the pitcher plants further attract prey.
A common type of pitcher plant that you’ll find in plant stores is called the trumpet pitcher (Sarracena leucophylla) which is a North American native. Very pretty, they could pass for orchids or calla lilies with contrasting colored veins on the leaves and cap-like lids hovering over the opening of the pitcher. They grow to be 1 to 2 feet tall and produce shiny maroon flowers in the spring.
They need at least 5 hours of direct sunlight a day to keep them from becoming floppy. Like the Venus flytrap it prefers wet feet so keep the pot in a saucer of water during the spring and summer growing season. Give it a cool drier treatment during its winter dormancy. There are many hybrids of these interesting plants for sale.
Darwin was fascinated by sundews (Drosera) saying that he cared more about Drosera than about the origin of all the species in the world. It is the largest family of carnivorous plants. The common name comes from the way their leaf hairs glisten like morning dew in sunlight.
Sundews are like living flypaper! This plant has an adhesive trap technique that lures bugs with leaf hairs that are sticky with promised nectar. The edges of the leaf then bend and curl around the trapped bug. Once captured, the plant produces digestive enzymes that asphyxiate it and eventually digest its prey. It takes several days; sundews are not as quick as fly traps.
There are many species of sundew and they are found all around the world. While small, they plants work well together; a large bog of sundews can capture millions of insects.
The Cape sundew (Drosera capensis) from South Africa is one you are likely to find for sale as a houseplant. Like the other carnivorous plants, they like it bright and wet but do not undergo a period of winter dormancy. It blossoms in late spring to early summer.
You can grow carnivorous plants at home; they need moist soil and lots of light. Never remove plants from the wild; only purchase from a reputable garden nursery.