Gardening Poisonous Plants

Touch-me-not Plants

Some plants have the ability to cause contact dermatitis (an unpleasant skin reaction).

Sometimes just simply brushing against the plant will do it, but in other cases, you actually have to bruise the plant or snap off a leaf or stem before a reaction will occur, because it’s contact with the sap that is harmful.

Note that in some cases, dermatitis will only occur if the skin is exposed first to the sap and then to the sun. This is called photodermatitis or phototoxicity. With these plants, there is therefore less risk of a reaction on a cloudy day.

Note too that sensitivity varies greatly from one individual to another: what can send one person to the hospital (and yes, that can happen!) may have no effect on another. But since you never know whether you’re sensitive or not, please wear gloves and long sleeves if you have to handle the following plants.

Buttercups* (Ranunculus spp.) can cause photodermatitis in sensitive individuals. Photo: pixbay.com
Dogbane (Apocynum androsaemifolium). Photo: Dcrjsr, Wikimedia Commons
Gas plant* (Dictamnus albus). Photo: www.specialplants.net 
Hogweeds* (Heracleum spp.). Photo: www.gardentags.com
Nettles (Uticaria spp. and Laportea spp.). Photo: Uwe H. Friese, Wikimedia Commons.
Poison-hemlock* (Conium maculatum). Photo: homeopathyonline.org.uk
Poison ivy (Toxicodendron radicans). Photo: meltonwiggins.com
Rue* (Ruta graveolens). Photo: www.qjure.com
Spurges (Euphorbia spp.). Photo: www.crocus.co.uk
Velvet bean (Mucuna pruriens). Photo: urbol.com
Wild Parsnip* (Pastinaca sativa). Photo: lcinvasives.org

*Plants causing photodermatitis.

Garden writer and blogger, author of 65 gardening books, lecturer and communicator, the Laidback Gardener, Larry Hodgson, passed away in October 2022. Known for his great generosity, his thoroughness and his sense of humor, he reached several generations of amateur and professional gardeners over his 40-year career. Thanks to his son, Mathieu Hodgson, and a team of contributors, laidbackgardener.blog will continue its mission of demystifying gardening and making it more accessible to all.

1 comment on “Touch-me-not Plants

  1. Again, as you know, the list could continue. Poison oak is similar to poison ivy. Some are allergic to primula, and many are allergic to some of the grevilleas!

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