Carnivorous Plants in Terraria/Vivaria

[Rat The Unloved]

Firstly, I do not claim to be an expert on the topic of Carnivorous plants, just an enthusiast who has raised a few of them extensively, and wants to share some of the information learned over the years to help in your viv-plant selection.

What is a Carnivorous Plant?
Carnivorous plants are the topic of intense debate between enthusiasts, sometimes to the point of exchanging blows. The general consensus, though, is that any plant which has evolved to trap and consume (directly or indirectly) some more ambulatory form of life is a Carnivorous Plant.

These are generally divided into classes based on how they catch their prey. These are broken into Active traps, Semi-active traps and Passive traps. None of these plants are entirely without danger to your vivarium inhabitants, but you'll be glad to know that most Carnivorous plants (called "CPs") don't catch anything larger than a fly too often. Some, of course, do catch large things just to be contrary.

Special Concerns: Nearly all carnivorous plants come from nutrient poor areas, as such they don't take kindly to water containing minerals, salts, or dissolved solids. It's best to water them with distilled water only. Nearly all carnivorous plants should be potted in peat, sphagnum moss, or coconut fiber. A familiar substrate to most of us. Some species (such as Cobra Lilies) are not listed because they cannot live in terraria. Others (like Bromeliads... yes, they're considered "potentially" carnivorous...) are better covered by other articles.

Types Of "CPs" - Active "Snap" Traps.

Venus Flytrap (dionaea muscipula).

Description: It is a compact, spider-like, plant with leaves ending in a modified "clam shell" - the trap. Each trap-side has three small trigger hairs inside of it, it is these hairs that, when stimulated, tell the clamshell to close, (hopefully) trapping prey. A fully mature Venus Flytrap plant, many years old (and in reality containing multiple plants) should be less than 10" across.

WOW factor: This plant comes in a huge number of both registered and unregistered cultivars, mostly centering around coloration and the shape of the traps. One newer cultivar "Wacky Traps" looks like something out of a scifi movie from the 50's. More of these plants exist in captivity than the wild (with an estimated 40K left out there) so be sure to pick a captive bred and raised specimen.

Danger Factor: Though this plant has a lot of "wow" factor, it's not that dangerous to adult frogs. Fully grown plants tend to have traps only about 1" long. Prey needs to be much smaller than the trap size in order for it to fully close, and subsequently "seal" to digest the prey. Small froglets and toadlets would be vulnerable to this plant, so I would advise against using it in vivaria where young, or exceptionally small frogs, are to be found. Some cultivars are very, very, small - consider these if you have any concerns.

Care/Feeding: This plant needs to be potted, not planted directly - though many people assume it to be tropical, Venus Flytraps are from the Carolinas in the U.S. and over-winter there at temperatures commonly found in your refrigerator, and additionally do not require high humidity - just damp soil. Plants older than one year need to be over-wintered (for about three months), and most keepers who live in climates ill-suited to this over-winter them in the fridge. Tthese plants only supplement their diet with insects - primarily ants and spiders - rather than living on them the way a true carnivore would. They will not deplete your housefly stores, either. A trick of the trap is that they close incompletely, allowing fruit flies and other small insects to escape. They aren't worth the plant's trouble! These plants do require high lighting, so be advised.

Rating: Poor. For an indoor vivaria or terraria there are a lot of better choices out there.

Utricularia - Bladderworts. (also covering "waterwheels")

Description: Bladderworts are aquatic or semi-aquatic plants which employ bladder-traps. The bladders exist at a lower pressure than the surrounding water, when they are triggered they open, sucking prey and water inside. The trap then closes, and begins digestion. These plants most closely resemble hornwort and other "spiny" aquatic plants, but put on a brilliant show of blooms.

WOW factor: Bladderworts are pretty - when blooming. A showy blanket of flowers across aquatic or boggy sections of a vivarium is one thing you can't beat with a stick. Unfortunately, at all other times they resemble moss.

Danger Factor: Absolutely dangerous to tadpoles. The traps can incrementally consume tadpoles, and other small fauna. In a vivarium where there are no tadpoles it can serve to control water fleas and other fauna introduced by plants (if those are not desired) and will absolutely help to curb a booming population of springtails.

Care/Feeding: These plants pretty much take care of themselves. Regular pruning and the occasional introduction of rinsed "Baby Brine Shrimp" will do the trick nicely. They do not need winter dormancy.

Rating: Fair. Great for mature vivaria with large, non-breeding, specimens.

Semi-Active Traps.

Butterworts (Pinguicula)

Description: Round, fat, rosettes of sticky, pale, leaves. Flowers, often briliantly colored, rise on very tall stalks from the center of the rosette. These plants trap prey with a flypaper-like surface.

WOW factor: This plant is low on the wow. It makes excellent plants for vertical walls/backgrounds, and because some of the tropicals are "ever blooming" it can put on something of a show.

Danger Factor: This is not an exceptionally dangerous CP - I would be hesitant to keep it around any toadlet or froglet under 1/3", "just to be safe". But it should not be a danger to anything larger.

Care/Feeding: Will decimate fruit fly populations. Even in a clean, modern, home - I always found 20-30 dead fruit flies stuck to the leaves of my butterwort. Tropical varieties do not require over-wintering, and temperate varieties don't "need" it, from my experience.

Rating: Fair. It's not very showy, but if placed in the right setup it will compliment it, and keep it clean.

Sundews (drosera)

Description: A rosette of either rounded, or elongated, leaves covered in extremely sticky (and sometimes irritating) mucilage that is used to attract and capture prey. Flowers rise on tall stalks and unfurl like fern fiddleheads. Their size is extremely variable from the tiny "dwarf" varieties to rather large, sprawling, cultivars.

WOW factor: The sparkling, reddish, dew-drops on properly maintained Sundews are something to behold. Dwarf varieties often have a pink hue, and fuzzy appearance.

Danger Factor: Larger sundews could entrap smaller frogs and froglets - just like most of the other plants listed. I consider them slightly more dangerous than any of the above, because an adult frog of the thumbnail size could easily become entrapped and starve to death.

Care/Feeding: Like Butterworts, these plants will snag fruit flies, and anything that cannot fight against the mucilage. Unlike butterworts, some variety of sundew actually "curl up" and can trap slightly larger prey like dragonflies. Placing them high up in a terrarium or vivarium, such as along walls or backgrounds, will keep them closer to the light. Here, they can clean up errant fruit flies, crickets and other feeder insects.

Rating: Fair. With the right placement and care they are very attractive plants.

Passive "Pitfall" Traps


Tropical Pitcher Plants - Nepenthes.

Description: Variable, vining, plants with long, slender leaves ending in a vase-like pitcher trap. These plants can range from fairly small, to extremely large. and come in a wide array of warm colors.

WOW factor: Well, just look through a few google searches filled with glossy, shining, Nepenthes traps and you tell me what the "wow" could be. A few even seem to have animal patterning.

Danger Factor: Most Nepenthes only catch insects - while a few of the larger species such as N. Raja are known to trap vertebrates. This is often accidental drowning, and does tend to lead to the death of the pitcher, so it's not something they encourage. If your frog can scale glass walls, it's reasonably safe with a Nepenthe but you would not be paranoid to check the traps daily. They do produce digestive enzymes, but are also known to catch rainwater (diluting said enzymes) and many frog keepers have noted that their darts happily breed in these pitchers.

Care/Feeding: These are some of my personal favorites. They thrive in a terrarium environment (especially N. "ventrata") , put on a lovely show of pitchers and foliage, do not require especially high lighting (unlike Flytraps). Filling the traps halfway with distilled water on a daily basis, and checking them routinely will go a long way to preserving not only the health of the plant, but sidelining any safety issues. There are a few varieties which do not secrete nectar, these may be preferable in terraria with fruit flies as a primary food source.

Rating: Good, granted you don't house it with anything clumsy.

North American Pitcher Plants (Sarracenia)

Description: Variable, hooded, trumpet-shaped plants reaching as high as 40+" in summer months. The hoods of these plants come in a wide range of colors, and cultivation has expanded this further. For the purposes of terraria, I strongly suggest avoiding anything but S. Purpurea and S. Rosea. Flowers rise on high stalks, and are specifically shaped to attract Bumblebees. These plants are for larger vivaria, often growing to a foot or more in height.

WOW factor: The color of "Purpurea" and related plants is brilliant. Ranging from deep purple-reds to pale green, often with striking veining. The flowers are also showy, often deep burgundy in color.

Danger Factor: Though most Pitchers have a hood which prevents rainwater from entering the trap, these don't. As such, their digestive ability is much less than others in their genera. The traps are also inclined, laying down rather than standing up. Any frog that can climb strait glass should be able to remove itself from one of these traps.

Care/Feeding: Cultivars of S. Purpure and rosea from the Southern U.S. need no over-wintering and will put up with higher humidity and soil saturation. Regularly adding water to the traps, should make for a happy co-existence. Though I have not had it confirmed, I suspect that the pitchers of this plant would be used by dart frogs for spawning.

Rating: Good, granted you don't house them with anything too clumsy.

Marsh Amphora / Sun Amphora - Heliamphora.

Description: Highly upright, fused, tubes with showy colors around the edges and tips, flowers rise on high stalks and resemble lilies.

WOW factor: One of the more lovely types of "CP", these plants come in the usual range of reds and greens. Their glossy colors tend to put on more of a show, and the blooms are some of the prettiest amongst CPs.

Danger Factor: Field studies have shown that most of these types of pitcher plants do not produce their own digestive enzymes, relying instead on bacteria to do the dirty work. Carnivory is lost in low-light species, meaning that they're even more harmless. Their pitfall traps should be navigable by all dart or tree type frogs.

Care/Feeding: These plants do well in terrarium setups, especially those with misting or fogging systems (simulating their lowlands habitats). They are some of the more rare species, and tend to have a higher cost associated.

Rating: Good for most types of setup, and most occupants (since the traps would be very hard for ground-dwellers to get into, and very easy for arboreal species to get out of).

Moccasin Pitchers - Cephalotus

Description: Compact, very fuzzy, pitchers resembling nepenthes. Pitchers remain small, with "giant" cultivars having only 3" pitchers at best. The colors range from pale green to nearly black.

Wow Factor: Let's be frank, they look like they're either about to break into song, or demand sacrifice. They are very, very, small, though.

Danger Factor: Though I have never personally raised Cephalotus, I've heard that it has difficulty harming flies. It's hairy pitchers may make escape harder for our amphibious friends, though.

Care/Feeding: Though they undergo a period of dormancy in the wild, they may be kept in a subtropical manner, and fair well like this.

Rating: Fair. I've never personally raised them, and they look a bit unwieldy for escape.

[UncleChester]

This is terrific, thanks! That's pretty hilarious that darts will breed in the Nepenthes kind of traps.

It probably won't do me much good being across the border, but where do you get your carnivorous plants from? Venus fly-traps show up regularly in grocery stores later in the summer, and I've seen types of sundews once or twice in greenhouses, but that's about it.

[LilyPad]

Very interesting, thank you for sharing!!

[Rat The Unloved]

Brian - I get mine from various places, just like you mentioned. Grocery stores, greenhouses, etc. However, there are numerous CP breeders and enthusiasts that are more than happy to share cuttings, seeds, and young plants.

[John]

Rat, I'd love to convert this to the article format. Do you have permission to use the photos in the article?

I've heard of darts breeding in pitchers too, incidentally.

[Rat The Unloved]

John, all of the photographs are from Wikimedia, all of them use a CC "Attribution, share alike" or "Public domain" - I forgot to put attribution, which I can't quite believe I did. I can't seem to find where to edit the post but:

Venus Fly Trap is H. Zell, Bladderwort is by M. Grathwohl, Butterwort is by K. Stuber, Drosera by D. Barthel, the Nepenthes is public domain ("Nep Grower"), Sarracenia is by P. Oliver, Heliamphora is by A. Eils, Cephalotus is by M. Jaeurnig.

[John]

Thanks, are you sure none are non-commercial? By the way, I'd like to put your real name in the article.

[Zathura]

Thanks for the information OP. I'm a very passive fan of CP's, in that I usually have a couple Flytraps and Pitchers (commonly found cultivars only) outside. They pretty much take care of themselves, I only have to water them with distilled about twice a week for pitchers and once a week for flytraps. I always wondered how they'd do in a terrarium though.