Houseplants that could be dangerous to you and your pets

I’m certainly not one for scaremongering, and the last thing I want to do is to stop you from growing houseplants in your home, however it is surprising how many common houseplants are really quite poisonous. For most of us it isn’t a problem; we are unlikely to tuck into our latest purchase from Ikea. However those with curious children and pets may want to take note. As with garden plants, there are surprises. We are aware that some are poisonous, whereas we are amazed that some of our favourites are equally toxic. Also those which are irritant or cause an allergic reaction to some may have no effect on others.

Those with some knowledge of houseplants will probably be aware of dieffenbachia, commonly known as “dumb cane”. The common name refers to the fact that the sap causes irritation of the mouth and swelling of the tongue; that is, if you suck it. All parts of the plant contain calcium oxalate which causes intense irritation of the mucous membranes resulting in swelling of the lips, tongue and palate. If you handle it normally and don’t eat it, it is quite harmless and very decorative. At one time it was one of the most popular foliage plants, despite its name and reputation.

What may come as a surprise is that the Swiss cheese plant, Monstera deliciosa, with its large shining leaves with characteristic holes, contains the same toxin and will cause the same reaction. So does spathiphyllum, the peace lily and syngonium, goose foot. Spathiphyllum is still regarded as one of the best foliage house plants with the benefit of flowers. It is often used in offices and houses to absorb the nasties given off by new carpets and furniture and is regarded as health giving. It is, but don’t eat it.

Sweetheart vine, Philodendron scandens also contains calcium oxalate. This trailing evergreen with its heart shaped leaves is sometimes promoted as a Valentine’s Day gift alongside red roses, champagne and chocolates. That’s great; just don’t get them mixed up.

The flamingo flower, anthurium is another surprise. This evergreen with its exotic, waxy blooms contains the same toxin. It is popular in Europe as a houseplant and extensively sold as a cut flower. Poisonous cut flowers are another story and there are plenty, but that’s a story for another day.

Most gardeners will be aware of the dangers of euphorbia sap. The milky liquid that oozes from stems of members of the spurge family contains terpenes and diterpenes which will cause sickness, vomiting and diarrhoea if swallowed, but the more likely effect is severe skin irritation. The same effect can be caused indoors by Euphorbia pulcherrima, the poinsettia and crown of thorns, Euphorbia milii.

Clivia miniata, that wonderful evergreen perennial with strap-shaped leaves and heads of orange flowers in early spring contains lycorine. If eaten it causes diarrhoea and vomiting. It’s a long lived plant that tends to get passed on via friends and family. The bulbs of hippeastrum (amaryllis) contain the same toxin. Think of how many are given annually as Christmas presents and how often do you hear of anyone mistaking them for onions? I think the risk is low and I would suggest that ingestion is unlikely.

In reality daffodils and hyacinths are equally toxic and more available. A daffodil bulb is more likely to be mistaken for an onion and I know of those that have. Please don’t try this at home, but I know I’ve eaten a very good lunch containing daffodils that my rather careless host thought were shallots. I lived to tell the tale.

In conclusion. Don’t eat your houseplants and keep them away from children and pets. Don’t eat anything unless it’s intended for consumption. Be careful when handling any plant material if you know your skin is sensitive and wash afterwards as a precaution.