I have always been fond of Korean azalea (Rhododendron mucronulatum), that hardy shrub whose pink flowers crack open just as the snow recedes. At the other end of the season, and the last of our azaleas to flower, comes another personal favorite: Rhododendron prunifolium (plumleaf azalea). Most of the Arboretum’s plumleaf azaleas grow along Meadow Road, amassed below towering black locusts in the Wolcott Bed. They escape notice until the middle of July, when their floral buds swell and burst open, when few woody plants bloom and temperatures are irrepressibly hot. Although it’s not comprehensively accurate (color ranges from deep red to nearly pinkish-orange),in this portrait, I’ll say the flowers are safety orange, that alarming shade reserved for prison jumpsuits and cautionary traffic cones.
This color should be taken as a warning, because Rhododendron prunifolium is rare in nature, limited to just a few dozen populations in the Chattahoochee River Valley and straddling the border of southern Alabama and Georgia. Neither disease nor insect is to blame; climate change (to date at least) is also not the culprit. Instead, the species totters on the brink simply because its preferred habitat—mesic forests, stream sides, and ravines—is disappearing due to logging and other development. In this respect, plumleaf azalea is like most other woody plants threatened with extinction: their natural homes are vanishing.
Shortly after the founding of the Center for Plant Conservation in 1984 (then based at the Arnold Arboretum), we began to collect the species in earnest. At present we grow thirty-four plants, mostly from Georgia’s Dade, Harris, and Stewart Counties. Preserving wild populations remains the highest priority, but it is important to have a back-up; while they grow here, their story is shared with others, and scholars from around the world come here to study them.
Let’s not ignore the fact that Rhododendron prunifolium looks good in the garden. For endangered species, being charismatic and attracting attention is a gateway to its security (just look at the giant panda). This means we must equally care for species whose security is questionable simply because they are less charming, at least in appearance anyway. At the Arnold, we make room for these plants, too.
Michael S. Dosmann is the keeper of the living collections at the Arnold Arboretum.