May 16, 2018 — Rhododendron season is here and our neighborhoods are bright with their blooms. Soon, it will be time for the annual Rhododendron Festival celebrating those charming shrubs that not only adorn our gardens, but also grow wild throughout our area.
With around a thousand species, rhododendrons are a diverse group of plants. Most species are found in Asia, but their natural range spans a large portion of the globe, including Oregon.
The most locally familiar species is undoubtedly the pink-flowered Pacific rhododendron that graces the sides of Highway 101.
For residents of Florence, the City of Rhododendrons, the shrub we affectionately call the ‘rhody’ is a source of community pride. However, in some areas of the world, rhododendrons are unwelcome pests.
The British Isles, for instance, spend millions of dollars fighting invasive rhododendrons that, despite their beauty, are harmful to native plant ecosystems.
Another aspect of the rhody’s darker side is its toxicity. As a natural defense system, many rhododendrons produce grayanotoxins which affect the nervous system and muscle function.
Found in all parts of the plant, the toxins can be fatal to livestock. This may seem of little concern for human health as few folks tend to snack on shrubbery.
However, grayanotoxins can be found in honey made from the nectar of rhododendron flowers. This so-called ‘mad honey’ has hallucinogenic, toxic effects known since ancient times. Over 2,000 years ago, Persian troops intentionally gave mad honey to their Roman foes who consequently became incapacitated and were easily overwhelmed.
Today, mad honey is eaten for its purported therapeutic properties. Folks believe it alleviates a variety of ailments from gastrointestinal issues to diabetes.
One of its most popular uses is for sexual enhancement. While people partaking of mad honey occasionally end up in the hospital, there have been no recent recorded fatalities thanks to modern medicine.
Local honey lovers need not be overly worried about products found in stores or farmer’s markets. Outside of regions where mad honey is intentionally produced (Turkey, for instance), poisoning risks are quite low.
As bees in most areas visit a variety of plants, they are unlikely to gather enough rhododendron nectar for their honey to have notable toxin levels, and commercially produced products tend to blend honey from different locations, further diluting any potential toxins.
So, as you enjoy the upcoming rhody festivities, admire the blooms, but know they do have a somewhat darker side.