Pinxterbloom Azaleas1 [Rhododendron periclymenoides (Michx.) Shinners] are blooming here in Northern Virginia, along with their cultivated relatives. Hmm, another name puzzle to work out.
Let’s take the common name first: it’s more straightforward. Pinxter morphed from the Dutch Pinkster or Pinksteren, the feast of Pentecost (or Whitsunday, for folks in the UK). Pinkster is still celebrated in the US today, particularly among Black communities of New York-New Jersey, i.e., the lands colonized by the Dutch. See the African American Pinkster Committee of New York (aapcny).
This article in Dutch on Pinksterbloem (Cardamine pratensis), botanically unrelated, gave me some clues as to the etymology.
The Flora of Virginia gives March-May as the flowering time for Pinxterbloom Azalea, which more or less squares up with the possible dates for Pentecost, 50 days after Easter, 10 May to 13 June.
Now let’s look at the specific epithet, periclymenum. Readers may know that oides is a suffix that means “like, resembling, having the form of.” Michaux called this showy shrub Azalea periclymenoides, presumably due to its resemblance to Woodbine, or European Honeysuckle (Lonicera periclymenum)—he doesn’t give an etymology.2
And what does periclymenum mean? Here, the trail goes sketchy. Google Translate suggests “dangerous,” but that reading is not backed up by my Latin-English dictionary or Roland Wilbur Brown’s Composition of Scientific Words (1956).3 However, sources suggest that both Lonicera periclymenum and Rhododendron periclymenoides are toxic. In particular, honey made by bees feeding on Pinxterbloom Azalea is called “mad honey” and can cause grayanotoxin poisoning. So… maybe “dangerous.”
A final note: the scientific name for Pinxterbloom Azalea is a pileup of synonyms, eventually sorted out by Shinners in Castanea 27: 94-95, 1962. I haven’t been able to locate a copy of this paper online.
1Also called Pinxter-flower, Pink Azalea, and (in Vermont) Election-pink.
2He also reports that it can be found in New Jersey.
3Although I do see Clymenus as a cognomen of Pluto.