Houseplant Toxicity Week: Part 5 (Unpleasant Plants)

If you have landed on this page because you are concerned about a child or pet who has eaten a plant, seek emergency medical help.

In the U.S., you can call Poison Control at 1-800-222-1222 (for children), the ASPCA at 1-888-426-4435 (for pets; $60 consultation fee applies), or the Pet Poison Helpline at 1-800-213-6680 (pets; $35 fee applies).

Part 5 of a seven-part-and-two-appendix series. (Part 1) (Part 2) (Part 3) (Part 4) (Part 6) (Part 7) (Appendix 1) (Appendix 2 - Index)

Part 5 is about plants which are not likely to kill you, or even to result in serious injury, but which may be capable of causing vomiting, bad skin or eye irritation, diarrhea, burning, itching, or other bad things, things that you should avoid experiencing if at all possible. Like . . . I guess Paris Hilton?¹ This is also the designation for a lot of the plants which are otherwise safe but bear thorns or spines that could puncture the mouth or digestive tract.

Abutilon hybridum (flowering maple) Causes skin irritation and/or allergic reactions in a few people; no info on pets but it does not appear to be particularly dangerous.

Acalypha reptans. I thought this was A. hispida for more than a year: boy is my face red.
Acalypha hispida, A. reptans (chenille plant, dwarf chenille plant) The sap appears to be able to irritate the skin and digestive tract, and skin irritation is occasionally reported. Although it is in the family Euphorbiaceae, it seems not to be a particularly dangerous plant (similar to Codiaeum variegatum, q.v.).
Alpinia zerumbet (shell ginger, variegated ginger) Occasional reports of skin and eye irritation, especially in people who habitually handle large amounts of plant material (e.g. commercial propagators). Toxicity by ingestion was not known to the authors of Toxicity. Minimal risk to the average indoor (or outdoor) gardener. Likely safe for pets.
Ananas comosus (pineapple) Leaves are pointed and spiny, which poses some mechanical risk. I know for a fact that the leaves can be eaten by rabbits more or less safely. Most pineapple-related medical problems are occupational: the uncooked fruit contains an enzyme which breaks down proteins, including those in skin (fingerprint loss is not unheard of), as well as sensitizing compounds which can cause rashes and other kinds of skin irritation. More or less safe around pets and children. Very soft-skinned reptiles / amphibians may be damaged by leaf spines. Unripe fruits can be extremely unpleasant if consumed (they're pretty hardcore purgatives, among other things), but don't appear likely to kill.
Araucaria bidwillii (bunya-bunya) Nobody seems to know whether Araucaria spp. are actually toxic, but this one is sharp and pointy enough that I can't imagine anybody wanting to try it to find out.

A small Araucaria heterophylla forest.
Araucaria heterophylla (Norfolk Island pine) Not mentioned by Toxicity or Handbook. Most websites list it as safe. Should be suitable for carnivorous reptiles and amphibians, and probably herbivorous ones too. The ASPCA website claims it's toxic to cats and dogs, but I kind of don't believe the ASPCA on this one.
Bougainvillea spp. (bougainvillea) Not common indoors, because it's hard to get the right conditions for it, but it won't poison anything if you can manage to make it work. Unfortunately it's also covered in thorns and can cause injury anyway, so deal with accordingly.
Capsicum annuum (chili pepper, bell pepper, etc.) Ingestion may cause pain, burning, etc., and in large amounts or in those unaccustomed to it, nausea and vomiting may follow. This is, sadly, occasionally used by criminally sadistic parents as a means of abusing their children, favored specifically because it doesn't leave any lasting marks, which I found upsetting when I read it. (Details for those who wish to be outraged and possibly sickened in footnote 2.) Skin irritation varies wildly from individual to individual, but is worst on skin which is already damaged or naturally thin (abraded, physically burned, open wounds, mucous membranes). Repeated occupational exposure can also result in extremely painful burning sensations. The smoke from burning Capsicum annuum plants may also irritate the respiratory tract. Getting juice in the eyes is very painful, as you'd expect. None of this really appears to constitute toxicity as the word is normally understood, and one assumes that children and pets would need, at most, exactly one experience with this to understand that this is a plant best left alone, so even though it has the potential to harm, I consider it more or less a safe plant. Though it's not often grown as a houseplant anyway.

NOID Chrysanthemum.
Chrysanthemum spp. (mum) The flowers may be toxic by ingestion, though neither Handbook nor Toxicity said they were. The main problem with Chrysanthemum spp. is that the flowers in particular, and to a lesser degree the leaves and stems, cause skin irritation in susceptible individuals. Which is all either book wanted to talk about. I would be wary of this one around kids and especially pets; while I doubt it kills, it does contain compounds similar to those in Hedera spp., q.v., and plus it just seems a little shifty.
Cissus quadrangularis As I noted in the profile for this plant, this is eaten on purpose by some people, though I get the impression that the amounts tend to be small. The only advice I could locate about preparing it was that one should not chew it, which suggests that it probably won't kill you, but it's probably painful or irritating to the mouth or digestive tract or whatever. Probably safe around kids and pets, though I'd hedge my bets and put it upon a high shelf somewhere anyway.
Citrus spp. (lemon, lime, orange) Rare allergic reactions have been reported, but the bigger danger is from the thorns on some varieties. The ASPCA website lists Citrus spp. as causing vomiting and diarrhea in both cats and dogs; I'm not sure if I think this is meaningful information or not, since almost everything in the world causes vomiting and diarrhea in cats and dogs.
Codiaeum variegatum (croton) Causes allergic skin irritation for some people, though repeated exposure appears to be necessary before that will start, and it doesn't appear to be especially serious when it does happen. Ingestion is supposed to cause a burning sensation, but that's as detailed as anybody gets. I'm not so much worried about this one.

Cryptanthus 'Elaine?' It's for sure a Cryptanthus, at least.
Cryptanthus spp. (earth star) Bromeliads are generally safe, though some Cryptanthus spp. have sharp points on the leaf edges. So it's probably not fun to swallow, but I'm guessing you could probably eat it anyway. Though, you know, don't.
Cuphea ignea (cigar flower) Some Cuphea species irritate the skin. C. ignea is not really known to be one of them, but Toxicity felt like warning everybody anyway. Draw your own conclusions.
Dahlia spp. Dahlias are generally considered safe, though they occasionally cause skin irritation, especially for those employed in handling the tubers. I wouldn't worry much about these w/r/t kids and pets.

Dizygotheca elegantissima.
Dizygotheca elegantissima (more correctly Schefflera elegantissima; false aralia) I did not find any evidence that Dizygotheca elegantissima is toxic; however, given its reassignment to the genus Schefflera, one should keep in mind that it may also contain calcium oxalate crystals and skin sensitizers like Schefflera actinophylla, q.v., and S. arboricola, and might be capable of causing pain and swelling if chewed, or causing skin reactions if handled a lot.
Euphorbia pulcherrima (poinsettia) Will be covered in Appendix 1, in a couple days.
Ficus benjamina (weeping fig, "ficus tree") Ficus spp. are more or less safe for most people in most circumstances, though I have heard of people developing asthma, wheezing, and similar respiratory problems around them, and I personally get itchy when I have to pick dead leaves out of them or whatever, which suggests I might be slightly allergic. If I am slightly allergic, then I'm just being normal: allergies to Ficus, and Ficus benjamina in particular, are pretty common among greenhouse workers, florists, etc. Aside from allergies and skin or eye irritation, Ficus spp. are pretty safe.
Ficus maclellandii (long-leaf fig, alii fig, 'Alii,' 'Alli,' 'Amstel King') As for Ficus benjamina, q.v.
Ficus microcarpa / nitida / retusa (Indian laurel) As for Ficus benjamina, q.v.
Ficus pumila (creeping fig) As for Ficus benjamina, q.v.
Kalanchoe spp. including K. blossfeldiana (flaming katy, kalanchoe, calandiva), Bryophyllum daigremontianum (mother of thousands, devil's backbone³), K. beharensis (feltbush) These do contain toxins, and in their native South Africa, they have been responsible for killing grazing animals, but for all their popularity as houseplants, there are "no cases" (says Toxicity) of Kalanchoe spp. causing poisoning by ingestion. Allergic reactions are known, but don't appear to be severe. Toxicity recommends that Kalanchoe spp. "be considered of slight or no toxicological significance." So I do.
Neoregelia cvv. Bromeliads are safe under most circumstances and to most species; however, many Neoregelia spp. have spines on the edges of the leaves, like Cryptanthus spp., which could in theory cause injury if swallowed.

Pelargonium x hortorum [something-something] 'Rose.'
Pelargonium x hortorum (geranium) Some people are sensitive to a few specific compounds in geranium essential oil, and occasionally people develop skin irritation or an actual allergy. They don't appear to be otherwise toxic, though, and should be considered basically safe plants around children and pets.
Sedum morganianum (burro's tail), S.rubrotinctum (jellybean plant), other Sedum spp. (stonecrop) Not a lot of information about these, but what there is suggests that they irritate some people's skin. Reports of toxic reactions are very rare, and usually there are no symptoms. Likely okay around children and pets, including reptiles and amphibians.
Sempervivum spp. (hen and chicks, houseleek, stonecrop) As for Sedum spp., q.v.

Solenostemon scutellarioides 'Rainbow Mix.'
Solenostemon scutellarioides (coleus, flame nettle) Cause allergic reactions in some people, and occasional non-allergic skin irritation. The later is more common in people who handle them a lot occupationally, though both reactions are rare. It appears to be safe if ingested.
Tradescantia pallida (purple heart, purple queen) A small percentage of people will develop skin irritation from handling them but this is of minimal consequence. Tradescantia spp. are one of the most commonly called-about plants for poison control centers, and are generally regarded as nontoxic for all species.
Tradescantia spathacea (Moses in the cradle, oyster plant) As for Tradescantia pallida, q.v.
Tradescantia zebrina (wandering Jew) As for Tradescantia pallida, q.v.

Yucca guatemalensis. These are an oddball variety I've had for something like ten or eleven years. It has gray variegation and is totally awesome. Variegated Yucca guatemalensis rule.
Yucca guatemalensis (spineless yucca) Neither Handbook nor Toxicity mentions Yucca guatemalensis. I did see a mention somewhere that ingestion causes vomiting and diarrhea in cats and dogs, but cat-and-dog digestive systems are obviously on a vomiting-and-diarrhea hair trigger anyway; I haven't seen anything about any other animal being poisoned by Y. guatemalensis. Flowers are incredibly unlikely indoors, but if some should form, they are said to be edible. The leaf tips, though spineless, do pose a slight mechanical danger, as do the serrated edges of the leaves: Lynn P. Griffith, Jr., author of the tropical plants growers' guide I like so much (see the sidebar), claims to have poked out an eardrum by bumping into the tip of a Yucca leaf.

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Photo credits: All are my own.

¹ Do we still hate her? She hasn't gone and done anything noble or selfless that I need to know about, has she?
² From Toxicity of Houseplants again: "Three children, ages 3, 5, and 7 were disciplined by their parents by placing a split jalapeno pepper in their mouths and setting a timer for 15 to 20 min. If the pepper was spit out, the child vomited [!], or swallowed the pepper, another pepper was placed, and another 20 min was started. The children experienced burning of the mouth, throat, and stomach, and burning of the anus when passing stool. The children cried at night from residual pain. [alarmed look] Vomiting and diarrhea were also seen as a result of the treatment. School authorities discovered the abuse, authorities were notified, and the treatments discontinued." [Hopefully because the parents had been torn to pieces by an angry mob, arrested, jailed, and torn to pieces again by angry prisoners, but the account stops there so I don't know. The ability of human beings to invent new ways of being horrible to one another should stop surprising me at some point, you'd think, but apparently not yet.] (Toxicity of Houseplants references Tominack, R. L. and Spyker, D. A., Capsicum and capsaicin -- a review: case report of the use of hot peppers in child abuse, Clin. Toxicol., 25, 591, 1987.)
³ (Included here because B. daigremontianum was at one time included in the Kalanchoe genus under the name Kalanchoe daigremontiana.) Also, it annoys me to an unreasonable degree that "devil's backbone" is apparently an acceptable common name for Bryophyllum daigremontianum, despite it having no backboney characteristics whatsoever, as far as I'm aware. Though it does have some devilish tendencies, I admit. Pedilanthus tithymaloides deserves the name a lot more, and is a better plant.