Carnivorous plants are some of the most exciting plants to grow for any garden, but they are perfect plants for a terrarium environment. Many of them are native to humid climates, and benefit greatly from the controlled humidity found in terrariums. They can be fairly tricky to grow successfully, although it is remarkably rewarding to do so. They are not recommended for the novice gardener or terrarium planter, but maybe after you’ve got a couple under your belt you’ll be willing to lay out a little bit of money to buy a truly exotic specimen like the sundew shown to the left.
Types of Carnivorous Plants
There are a wide variety of carnivorous plants, from the ever-popular Venus Fly Trap to the sedate pitcher plant, but there are five main mechanisms that plants can use to go from photosynthesising to predator:
- Snap traps, when leaves move rapidly to capture an insect
- Bladder traps, which create a small vacuum that sucks an insect in
- Lobster-pot traps, which prevent insects from escaping using inward pointing hairs or spines
- Flypaper traps, which glue insects down like the name suggests, and
- Pitfall traps, where an insect falls into a container usually filled with some kind of digestive juices
They all sound pretty cool, right? You’re not wrong – and if you’ve ever had a problem with fruit flies in your kitchen, maybe a terrarium full of carnivorous plants is exactly what you need! You know that old saying, you catch more flies with honey than you do with vinegar? Well, you’ll catch even more with some pet carnivorous plants! If you can really call a plant a pet, I suppose. Anyways =)
Carnivorous Snap Trap Plants
Snap traps are probably the most dynamic of the carnivorous plant types, although it’s a very small family, with only two known species. The Venus Fly Trap, with its iconic shape and deep red internal membranes, is also one of the most beautiful carnivorous plants. To learn more about the Venus Fly Trap, read our in depth exploration of them here.
The other species of snap trap is actually aquatic, and quite rare in the wild. Known as the waterwheel plant, it captures small underwater invertebrates in a similar way to the Venus Fly Trap. It actually has no central root stem, and simply floats along gently through standing water until its small snap traps are triggered, closing in under 20 milliseconds, which is much faster than the human eye can follow.
Both species of snap traps use small spines inside the traps to trigger their motion, although only the Venus Fly Trap does well in captivity. For those of you who are more interested in aquatic ecosystems and have the patience and wherewithall to find a specimen, you may want to try growing waterwheel plants, but they are not recommended for beginners.
Bladder Trap Plants
Bladder traps are used by only one family of plant: the perhaps unimaginatively named bladderworts. But what they lack in name recognition, they make up for by some pretty cool physics. They can live on land and underwater, and both types pump the water out of their bladders in order to create a vacuum. When prey touches the trap, the seal is broken, air or water rushes in to fill the vacuum, and the prey is sucked in along with it where the bladderwort can digest it at leisure.
Bladderworts also have flowers which are highly prized by many carnivorous plant cultivators, as they somewhat resemble orchids and snapdragons. Unfortunately for those of us who really are fans of the trapping action, the aquatic species tend to have the larger bladder traps, and are also a bit more difficult to cultivate.
Lobster Pot Trap Plants
These are actually the closest to the type of insect trap you might use to get fruit flies out of your kitchen, although most plants who showcase these types of traps are aquatic, and use them to eat protozoa in the water. Basically, the prey is drawn in to a trap by some lure, and then finds it difficult or impossible to find the way out again, when it then dies, gets digested and turned into nutrients for the plant.
Flypaper Trap Plants
Flypaper traps are found on some of the most beautiful carnivorous plants, such as those in the genus Drosera, commonly known as sundews. Sundews are found all around the world except in Antarctica, and have long, brightly coloured tendrils that appear almost like furry tentacles. These tendrils are tipped with a sticky substance that both attracts and traps insects, which is where they get their name, as the droplets sparkle like dew in the sunshine. After snap trappers and bladder trappers, sundews are some of the most active plants, with the ability to bend their tendrils at 180 degrees in under sixty seconds.
Sundews are also one of the more popular carnivorous plants after the venus fly trap, and with good reason – they’re beautiful!
Pitfall Trap Plants
Last but not least, we arrive at the quiet and relaxed pitfall trap. This type of trap probably ties with the lobster pot style of trap for lack of animation, but the plants which showcase this type are also much easier to grow than lobster pots, and they’re all terrestrial, which makes them much better suited for the terrarium environment.
Pitcher plants are the most commonly known pitfall trap plants, and there are a number of different species that are thought to have evolved independently. The general principle is the same, however. A specialized leaf acts as a ‘pitcher’, which is filled with water or sometimes special digestive enzymes, and traps insects as they come into contact with the liquid surface tension, leaving them unable to escape. They eventually become exhausted and drown, where they are dissolved and turned into nutrients to feed the pitcher.
Caring for Carnivorous Plants
It’s important to realize that carnivorous plants are some of the most difficult to grow in terrariums. As you can see from reading above, many are aquatic, and they all have fairly specific growth requirements. They’re incredibly rewarding to grow, but they may not be the best choice for the amateur indoor gardener, even though they’re some of the most interesting.
Never trigger their traps without prey, as it takes a tremendous amount of energy for them to reset, and without receiving the nutrients from a successful capture, they can quickly become exhausted and die. If you do decide to grow some carnivorous plants in your terrarium, let them feed themselves!