Why do plant names change? Name alterations present a challenge for growers (updating plant tags, catalogs, signage), teachers (memorizing and educating with current names), and gardeners (finding the desired plant). So why not let well enough alone? As it turns out, there are good reasons for changes.
First, a quick taxonomy note. We owe the Genus/species/‘Cultivar’ binomial naming scheme to 18th century Swedish naturalist Carolus Linnaeus. Latin Genus is always capitalized and italicized. It is followed by lower case species, also Latin and also italicized. The species is descriptive. For instance, ‘globosa’ means globe-shaped or ‘japonica’ means Japanese. Any specific cultivar is capitalized and surrounded by single quotes. Example: Cercis canadensis ‘Forest Pansy.’ These names are identical across all countries, all native languages. A species name is never used without its genus.
A change in plant name may occur to correct a mistake. If two different botanists named the same plant, for instance, the earliest name will be adopted as the correct one. And a plant cannot have two different genus/species labels – chaos in the garden!
Just as human DNA testing has increased in sophistication, plant genome mapping has caused the reclassification of some plants. One such reclassification is Coleus. We all know a Coleus when we see one, right? In 2006, Coleus had a name change to Solenostemon. In 2012, it was renamed to Plectranthus. And in 2019, it was renamed, again, to Coleus. Whew!
One of my favorites, Sedum spectabile ‘Autumn Joy’ is now Hylotelephium telephium 'Herbstfreude' which looks very much like the naming botanist’s cat walked across the keyboard.
The reclassification that still has me scratching my head is our southern icon, the native Dogwood, Cornus florida. Since 2014, it has officially become Benthamidia florida, although I see no evidence of changes in our local plant centers. Old habits die hard. I’ll just call them Dogwoods.
Finally, we can call this plant Coleus again.