by Melody Kendall

After working an hour or so doing some fall pruning in my garden, the song ‘Oops I did it again' came to mind as I rushed into the house for a quick wash on my itching arms. It seems every time I work in my garden I forget that the gaillardia plant is a skin irritant. After one such recurring ‘oops' moment I decided to do some research to see what other common landscape plants might cause similar skin discomfort when being nurtured.  

In my garden alone there are quite a few………

- Ranunculus and anemones are usually some of the first to bloom in my garden. The whole ranunculus family, when injured, secrete a toxin called protoanemonin. This toxin could cause a rash and itching and as possibly blisters on contact. 

- Strawberries (Fragaria × ananassa) are one of the few food crops that we grow.  The leaves and fruit might cause a skin reaction and the fruit, when consumed, could cause a skin rash as well.

- Chrysanthemums are a new addition to my landscape.  The sap contains the phytochemical compound alantolactone, which can irritate skin on contact and increase sensitivity to sunlight.

- The various agapanthus in our garden could cause dermatitis as the juice or sap of these plants may cause a skin rash or irritation.

- The azaleas (Rhododendron spp.) pose a major toxicity issue if consumed. They contain toxins called grayanotoxins.

- Our new black locust ‘twisty baby' (Robinia pseudoacacia)presents quite a danger as the leaves, flowers, branches, seeds and bark contain the toxalbumins, robin and phasin. The trees themselves are considered invasive in some regions and a detriment to surrounding foliage because they are reputed to secret toxins in the soil that inhibit the growth of  the surrounding plants. This is called allelopathy which is the chemical inhibition of one plant (or other organism) by another, due to the release into the environment of substances acting as germination or growth inhibitors.

- The bougainvillea and roses have thorns to watch out for.

- The naked lady (Amaryllis belladonna L.) is always a plant that I consider to be a fun addition to my landscape. The plant's bulbs sprout bright green leaves in winter and early spring that then die back.  I am continually delighted when these plants then push up those wonderful ‘naked' stems topped with lovely flowers in summer. Watch out! All parts of this plant are poisonous if ingested.

- Our climbing plants the trumpet vine (Campsis radicans), clematis and star jasmine (Trachelospermum jasminoides) have sticky sap that cause skin irrigation, stain clothes and gum up tools.

- The sap from iris, poppy (Iris germanica), lily (Lilium) and daffodils (Narcissus) could cause a mild skin irritation

Looking around the neighborhood I found quite a few toxic examples as well……….

- Agave plants:  Many of these plants have thorns. Sometimes huge thorns. The juice or sap of these plants contains needle shaped oxalate crystals which can cause skin irritation and, if ingested, swelling of the throat and stomach upset.

- Allium plants: Don't eat the plants or the beautiful blooms as they might cause minor illness or vomiting.

- Angel's Trumpet (Brugmansia): These are really toxic if any part of the plant is ingested. Doing so could require a quick run to the emergency room.

- Gingko tree (Ginkgo biloba): In your rush to remove this tree's extremely smelly fruit from the ground beneath the canopy be sure to wear gloves as the juice of the fruit might cause dermatitis.

- Lobelia plants: A double jeopardy where if you ingest the plant it is a major toxic hazard and if you get some of the sap on your skin you can get a rash.

- Solanaceous:  Plants-Many gardens contain plants from this family. The Angel's Trumpet above is only one of quite a large list.  These plants are notorious for being toxic, exceedingly so in some cases. But, on some of the plants only portions are toxic.  Tomato and potato plants are examples as the fruit of the tomato and the tuber of the potato are perfectly edible but the leaves and stems of both are highly toxic. Be aware.

- Poinsettia plants (Euphorbia pulcherrima)-This is a traditional Christmas plant.  Look out as the sap can cause skin irritation and don't nibble on the leaves or stems as they are a minor toxic hazard. 

- Pyracantha plants have those great red berries but don't eat them as they are mildly toxic and, if pruning the plants, wear gloves as the sap could make your skin react with a rash.

- Coast Redwood trees (Sequoia sempervirens): There are quite a few of these trees in my neighborhood.  I had no idea that the leaves were a minor toxic hazard and that with contact the sap and leaves could cause a skin irritation.

- Oleander plants (Nerium oleander) are quite prevalent in older landscapes as they were a very popular "fill in" plant.  According to the National Institute of Health "all parts of the oleander plant are toxic and can cause severe illness or death, including the leaves, flowers, twigs, and stems. The plant is so poisonous that even drinking water from a vase holding a bloom can cause a severe reaction." This plant might not be a good one to include in your landscape and, if you intend to remove existing plants, dress appropriately!

All the plants on the above list are only a sampling of the possible plants that might cause a minor and/or major toxic reaction. At first blush, all this information might make you feel that you should be donning a hazmat suit when doing any yard work. But remember forewarned is forearmed. My advice is to read up on all the plants in your garden and plan each work session defensively. Being informed will have the added benefit of being able to ID all of your garden plants and be better able to care and maintain your landscape. 

I feel that there is more in the gardening plus column that far outweighs the negative column. There won't be radical changes in my gardening modus operandi.  Armed with all this information I will dress appropriately and carry on. Then, taking into consideration my memory issues, I can hopefully avoid any further ‘oops' moments. 

Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143.  Volunteers will get back to you after they research answers to your questions.

Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.

Photo credits: Mel Kendall

Information links:

UCANR-'Safe and poisonous garden plants'              https://ucanr.edu/sites/poisonous_safe_plants/files/154528.pdf