Sweet Rhododendrons

Today’s garden-themed post features a flower which I have never planted—indeed, having grown up in farm country, I am somewhat alarmed by this plant. Yet, as I walk around the neighborhood I am beguiled by its seductive beauty (plus there aren’t too many ponies in Brooklyn these days). I am of course talking about the Rhododendrons, a large genus of woody heaths which speciate most prolifically in Asia around the Himalayas, but also can be found throughout Eurasia and into the Americas (particularly the Appalachian Mountains). Actually, I was dishonest in the first sentence (it’s a national fad these days), I have, in fact, planted azaleas, which are a species of rhododendrons, but I am writing here about the big showy purple rhododendrons, and we will leave real talk about azaleas for another spring.

In the In the Victorian language of flowers, the rhododendron symbolizes danger and wariness. This is fully appropriate since some of showiest and most highly regarded rhododendrons are indeed poisonous: they contain a class of chemicals known as grayanotoxins which affect the sodium ion channels in cell membranes. Rhododendron ponticum and Rhododendron luteum are particularly high in grayanotoxins. Humans are somewhat less susceptible to these compounds than other mammals (like poor horses, which just are apt to drop stone dead from browsing on rhododendrons), however, as is so often the case, our cleverness, grabbiness, and our taste for sweetness also puts us at higher risk for consuming grayanotoxins.

Bees are drawn to the large colorful (and sweet) flowers of rhododendrons and they use the grayanotoxin rich pollen and nectar to make honey. If a bee hive incorporates a few ornamental azaleas into the honey, this is not too dangerous, but in regions where rhododendrons dominate and all come into bloom at once, the resultant honey can be extremely dangerous. This “mad honey” is said to cause hallucinations and nausea in lower doses, but in larger quantities it can cause full body paralysis and potentially fatal breathing complications. Like the hellebore, rhododendron honey was one of the first tools of deliberate chemical warfare. Strabo relates that Roman soldiers in the army of Pompey attacking the Heptakometes were undone by honeycombs deliberately left where the sweet toothed Romans would find them. It seems best to appreciate rhododendrons by looking at them. In fact, if you live in a Himalayan fastness surrounded entirely by rhododendron forests (or if you are attacking the Greek people of the Levant) maybe don’t eat honey at all…not until later in the summer.

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