When Botanical Names Change: Understanding Plant Reclassification
Did you know that rosemary, the herb you sprinkle on your roast, is technically a sage? Botanical names aren’t just labels; they reflect a plant’s genetic relationships. However, advancements in genetic research sometimes reveal surprising connections, leading to reclassification. While this can be frustrating for gardeners and industry professionals, these changes provide a clearer understanding of plant lineage and ensure scientific accuracy.
One such reclassification occurred in 2017 when the well-known herb Rosmarinus officinalis (rosemary) was moved into the Salvia genus. Based on molecular phylogenetic studies, researchers determined that rosemary was more closely related to other Salvia species than plants in its former genus. As a result, its scientific name changed to Salvia rosmarinus.
Who Decides?
Plant name changes are determined by taxonomists and scientists who study plant classification. The International Code of Nomenclature for algae, fungi, and plants (ICN) governs the naming process, ensuring consistency worldwide. Changes are typically proposed based on genetic research, reviewed by the botanical community, and published in peer-reviewed journals. Organizations like the International Botanical Congress (IBC) and taxonomic groups specializing in specific plant families play key roles in approving and adopting these updates.
Why Do Plant Names Change?
Traditional classification relied on observable traits like leaf shape, flower structure, and growth habits. However, modern DNA sequencing has revealed deeper genetic relationships that aren’t always apparent from morphology alone. When a plant’s genetic data shows that it fits better within a different genus, taxonomists update its classification.
Other Notable Plant Reclassifications
Chrysanthemum spp. → Dendranthema spp. (then back to Chrysanthemum) The reclassification of certain chrysanthemums to Dendranthema in the 1990s caused an uproar in the horticultural industry. Due to public and industry pushback, taxonomists later restored many species to the Chrysanthemum genus.
Aster spp. (North American species) → Symphyotrichum spp. Many North American asters were reclassified into the genus Symphyotrichum after studies revealed they were genetically distinct from Eurasian asters. For example, the New England Aster is now Symphyotrichum novae-angliae.
Sansevieria spp. → Dracaena spp. The popular Sansevieria genus, known for snake plants (e.g., Sansevieria trifasciata), was merged into Dracaena in 2017. While the new name Dracaena trifasciata is taxonomically correct, “Sansevieria” is still widely used in the trade.
Eupatorium spp. → Eutrochium spp. Once placed in Eupatorium, Joe-Pye weeds were reclassified into the genus Eutrochium due to genetic distinctions from other bonesets and thoroughworts.
Prunus caroliniana → Laurocerasus caroliniana The Carolina cherry laurel was moved into Laurocerasus, aligning it more closely with similar species.
Liquidambar styraciflua → Altingia styraciflua Some taxonomists have proposed moving sweetgum to the Altingia genus based on phylogenetic studies.
Cornus florida → Benthamidia florida Some dogwood species, including Cornus florida, have been reassigned to Benthamidia in certain classifications.
Fraxinus excelsior → Ornus excelsior European ash trees have undergone classification revisions that link them more closely to Ornus species.
Phellodendron amurense → Tetradium amurense The Amur cork tree has been reassigned in some taxonomic treatments to Tetradium.
Implications for Gardeners and the Nursery Trade
For professionals in horticulture, landscape design, and nursery production, these changes mean:
Updating plant labels and catalogs to reflect the correct names.
Educating customers about changes so they can find the right plants.
Allowing time for industry adjustment—sometimes decades—as designers and nurseries don’t always adopt new names quickly. Take Cornus stolonifera, for instance: though reclassified as Cornus sericea by the late 20th century, it’s still seen in designs today. This debate stretches back to Carl Linnaeus, who named it Cornus sericea in 1753. Still, North American botanists favored Cornus stolonifera for its stoloniferous (suckering) habit. Taxonomists later ruled Cornus sericea had priority under nomenclature rules. Yet, older references and some catalogs cling to the outdated name, showing how practicality often lags behind science.
Pro tip: When shopping for plants with newly changed names, search by old and new scientific names—nurseries might not update their systems overnight!
While reclassification can be confusing, it enhances our understanding of plant relationships and ensures accuracy in the long term. Staying informed about these updates helps maintain consistency in the field and improves communication between professionals and consumers.
Key Takeaway
Genetic research that clarifies evolutionary relationships drives botanical reclassifications like Rosmarinus officinalis becoming Salvia rosmarinus. While the process can be disruptive, it ultimately leads to a more precise understanding of plant taxonomy.