Beware the pretty ones. They can beguile the eye but poison both mind and body: Foxglove, Lily of the valley, Lantana, Wisteria, Oleander, Azaleas and Rhododendrons. Pretty plants all in a row, lovingly tended there in our gardens, silently synthesizing deadly toxins intended to keep herbivores and omnivores at bay. Make a “herbal tea” from any of these and it will quickly and definitively belie the notion that “All Natural” products are inherently safe and naturally superior
Rhododendron periclymenoides, also known as Pinxster Flower or Native Azalea, is a non-descript, somewhat spindly shrub in our Eastern Forests for about 50 weeks of the year. For the other fortnight, contemporaneously with the wild dogwoods, it participates in the profusion of vernal color. I am fortunate to have a native Pinxster Flower outside my kitchen window that predates my house. (Above) It survived unscathed when my home was built and I have nurtured it ever since.
To me, its delicate pink-white flowers resemble honeysuckle caught mid-act transforming into rhododendron blooms. They produce a pleasant, heady scent that is described as similar to petunias. Whatever the aroma, insects come flocking, especially tiny bees. And here, the story takes a darker turn.
As already noted, rhododendrons are toxic, including the Pinxster Flower. Ingestion of any part of the shrub in quantity can cause clinical distress. The noxious agents are grayanotoxins, a class of neurotoxin, that block the inactivation of sodium channel receptors, thereby causing cell dysfunction. (1)
Even the flowers’ nectar contains grayanotoxins, thus honey made from it by those busy bees is similarly toxic, the aptly named “Mad Honey.” Humans who ingest this sweet delight can develop gastro-intestinal symptoms such as vomiting and diarrhea in addition to the cardiac effects of hypotension and irregular heartbeat. Although this mechanism is the most common form of rhododendron toxicity in the United States, it is not a significant public health problem.
Where there is plant-based toxicity, there is also opportunity in its pharmacological effects. As a consequence, in traditional Chinese medicine, Mad Honey (presumably appropriately titrated) has been used as an aphrodisiac, for hypertension and as an alternative therapy for gastrointestinal disorders such as peptic ulcer disease, dyspepsia and gastritis. (1)
1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9080652/#:~:text=Mad%20honey%20has%20been%20commonly,hypertension%20for%20a%20long%20time.
