Plumbago flowers range from light blue to blue, but can also be found in white (P. auriculata var. alba) or deep blue (P. auriculata var. ‘Royal Cape’) flowers. The leaves are a glossy green and grow to 5 cm long. This family of shrubs has an Ogren Plant Allergy Scale (OPALS) score of 4 or less and has been promoted by horticultural and human health organisations in Australia and overseas, as a suitable plant for use in low aero-allergen ‘asthma friendly gardens’. However, the entire plant, including the root, contains ‘plumbagin’ – a toxic organic naphthoquinone derivative that is reported to induce an acute toxic contact vesicular (blistering) reaction in humans. Death in humans from extensive use of the sap as a medicinal rub has also been reported.
Oak Flats Vets, with the help of specialist dermatologist vet, Dr David Robson, have had a case of a blistering skin condition in a dog (following contact with a Plumbago shrub) written up and published in the Australian Vet Journal in August 2016. The condition was very painful and distressing to the dog but responded to quick, simple and affordable treatment. The condition could be confused with some serious immune conditions that would require on-going long term medication. Our paper alerts and reminds vets and owners to look for Plumbago and other irritant/contact risk plants when presented with such a blistering and painful condition. The plant should not be confused with a somewhat similar looking plant-Duranta- that also shares the Sky Flower common name. For more on Duranta, read Dr. Aine’s Blog in the Pretty Poisons section.