Whether planted outdoors or enjoyed as houseplants, Plectranthus species offer one of the widest arrays of fascinating foliage. They are heavily veined and come in solid colors as well as variegations. Bicolored leaves -- such as green on the top and burgundy on the bottom -- are common. Some species have plump, succulent leaves while the foliage of others is flatter and more hairy -- traits that help them conserve moisture and withstand heat and drought.
Plectranthus is a genus separate from but closely related to Salvia and Coleus. It's important to note that at Flowers by the Sea, we grow many species of Salvia, some Plectranthus, and no Coleus (even though we love the vivid, multicolored foliage of C. scutellarioides).
A bit of disambiguation is necessary to clarify what we mean when identifying a plant as a Plectranthus. Naming confusion exists in plant catalogs and garden centers regarding whether Coleus species should be called Plectranthus due to British botanist John Kenneth Morton placing them in the Plectranthus genus in 1962. However, the two were reclassified as separate entities in a 2019 study led by Kew botanist Alan J. Paton ["Nomenclatural changes in Coleus and Plectranthus (Lamaiaceae): a tale of more than two genera" (https://doi.org/10.3897/phytokeys.129.34988)].
Although the flowers of these easy-to-grow plants are less spectacular than their leaves, some kinds of Plectranthus offer lovely floral displays including blues, lavenders, pinks and whites. Many are fragrant. Modern day plant explorer and botanist Ernst van Jaarsveld, author of The Southern African Plectranthus, numbers the genus at about 350 species. Van Jaarsveld says these mint family (Lamiaceae) members are found in Africa, Australia, India and Japan with 53 native to South Africa and the neighboring country of Namibia.
Plectranthus grow well in partial shade with some even thriving in full shade. In the U.S., they are excellent as:
Many Plectranthus seem designed for life in hanging baskets - indoors or outside - where they can trail over container edges. At some point (we're not sure exactly when) various species became popular in Scandinavia as houseplants and were commonly called "Swedish Ivy" despite having nothing to do with Ivy (Hedera spp.).
In the 1970s, some types of Plectranthus became popular decorative elements in U.S. restaurants known as "fern bars." Certain species are still referred to as Swedish Ivy. These include P. verticillata (or P. australis), P. oertendahlii and P. strigosus, all of which are native to South Africa. However, Van Jaarsveld only refers to P. oertendahlii as Swedish Ivy.
Use of scientific names is important when shopping for Plectranthus, because some species are tagged with a plethora of common names. For example, Plectranthus amboinicus (sometimes botanically misidentified as Coleus amboincus) is commonly called Allherb, Big Thyme, Broadleaf Thyme, Country Borage, Cuban Oregano, French Thyme, Indian Borage, Indian Mint, Mexican Mint, Mexican Thyme, Soup Mint, Three-in-One Herb, Mother of Herbs, and Queen of Herbs.
To add to the naming confusion, Plectranthus as a group are commonly called Spurflowers. This is due to the spur, or tubular extension, at the base of P. fruticosus, the first plant identified in the genus. French botanist Charles Louis L'Heritier de Brutelle named the genus and P. fruticosus in 1788. In Latin, plectron means spur and anthos is flower. However, few Plectranthus have spurs, something L'Heritier de Brutelle didn't know.
(Lush Lavender Spur Flower) Plumes of lavender blue flowers rise from the lush, richly colored foliage of Plectranthus ciliatus ‘Zulu Wonder’ on velvety, reddish-purple spikes. The coarsely toothed, mid-green leaves are reddish-purple on their undersides.