Reviving Paradise: Beware of toxic Japanese wax tree

Last week I attended the KZN Invasive Alien Species Forum hosted by the well-respected South African National Biodiversity Institute (SANBI) Directorate on Biodiversity Evidence at the Krantzkloof Conference Centre.

It was a morning of interesting talks, presentations and discussions, including, near the end, a profile of the Japanese wax tree (Toxicodendron succedaneum) by Mieke van Tienhoven.

As you may be aware, The Green Net’s beautiful and informative Biodiversity Calendar seeks to educate people about both Indigenous Gems and Alien Invasive Plants, and this plant appeared in September 2025 as the AIP to remove, with warnings that the entire plant is poisonous.

Nothing had prepared me for what I heard at the SANBI forum, so I urge you to read further to understand this beautiful, but dangerous Category 1B plant which may not be owned, grown, moved, sold, given as a gift or dumped into waterways. Although thankfully not too common, there are 83 recorded sightings registered on the iNaturalist App, including one in Harding. Trust me, you do not want to engage with this plant unless you are very well prepared.

Rhus tree (or Japanese wax tree) is a small deciduous tree or large shrub that is highly toxic and allergy causing.

The tree reaches a maximum height of 8-12m and has small branches with leaves that change from green to red as winter approaches. Its beautiful autumn foliage has led to it being planted outside Asia as an ornamental plant, often by gardeners who were apparently unaware of the dangers of allergic reactions which can take up to two weeks to manifest! The symptoms are difficult to diagnose and treat, which can lead to increased discomfit and permanent scarring with recurring symptoms. Repeated exposure exacerbates the allergic reaction.

The toxin can be transferred by simply brushing against the plant, as was explained in the case of a horse rider who fell ill weeks after riding, and animals are not spared either. All parts of the plant contain urushiol, which causes characteristic dermatitis associated with exposure.

Proper protective equipment should be used with specific instructions to use vinyl gloves as urushiol can penetrate rubber or latex gloves.

As part of decontamination, all clothing and objects with potential exposure should be thoroughly cleaned with warm water and detergent. If you do happen across this plant, avoid cutting or slashing which could lead to sap splashing.

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