Plectranthus barbatus (Blue Spur Flower) - A fast growing erect large shrub to 6 to 8+ feet tall by as wide with thick stems holding large 4- to 6-inch-long ovate light green leaves that are lightly fuzzy and have small dentations along the margins. In fall through late spring and often well into summer appear the showy dark blue-purple flowers in stacked verticils, each holding 6 to 8 flowers, arranged along in a 10-inch-long inflorescence.
Plant in full sun to part shade and water occasionally - pretty drought tolerant but certainly looks much lusher with some regular irrigation. Will resprout after a frost freezes top growth and seems root hardy to 20 to 25 °F but evergreen only in near frostless conditions - useful in USDA zones 9 -11. This plant has long lasting blooms and will even flower in the shade but it also looks good even with just the foliage and is great for adding a somewhat lush tropical look to the garden or as a backdrop for other smaller flowering plants. It is used as a hedge-plant in Kenya and Ernst van Jaarsveld notes in his book The South African Plectranthus that in South Africa this plant "makes an attractive large shrub with dark blue-purple flowers, popular with gardeners and is commonly grown where frost is not severe".
Plectranthus barbatus is considered native to a huge range from Pakistan, India, Nepal and Ceylon south through Arabia, Sudan, Eritrea, Ethiopia, Somalia, East African, South Tropical Africa and naturalized into southern Africa. Henry Charles Andrews first described this plant in 1809 as Coleus barbatus but Andrews did not indicate the specific locality, only noting plants grown from seed collected in "Abyssinia" (Africa). It is thought that the likely source was Henry Salt, who was collecting in Eritrea and the Tilgray region of Ethiopia from 1802 to 1806 on an expedition with George Annesley, the Earl of Mountnorris and Viscount Valentia.
Plectranthus barbatus can be seen in gardens throughout Santa Barbara, where it has been cultivated for more nearly 30 years. We believe it was first introduced into our area by Daryll Combs of Daryll's Exotic Plants in the 1980's under the incorrect name Coleus lanuginosus. Coleus lanuginosus, now Plectranthus lanuginosus, is a much smaller plant, but also with attractive blue flowers. This plant is also grown in the California nursery trade as Plectranthus fruticosus 'Winslow' because it was apparently inadvertently labeled as such at the San Francisco Botanic Garden. It is also sometimes listed as Plectranthus comosus, an invalid name first associated in the late 19th century with Plectranthus ornatus and later listed as a synonym for Plectranthus barbatus. This plant is grown throughout the world, likely because of its herbal uses, pharmaceutical qualities and in India it is grown for its edible roots and in parts of Africa as a substitute for toilet paper. Given its wide natural range and cultivation elsewhere, it is not surprising it has many additional common names such as Indian Coleus, Kaffir Potatoe, Abyssinian Coleus, Marundhu Koorkan, False Boldo and Kikuyu Toilet Paper.
In 2018 Alan Paton, Head of Collections at the Royal Botanic Garden Kew, did a revision of Plectranthus and related plants (Paton, A.; Mwanyambo, M. & Culham, A. (2018). "Phylogenetic study of Plectranthus, Coleus and allies (Lamiaceae): Taxonomy, distribution and medicinal use". Botanical Journal of the Linnean Society. 188 (4): 355–376.). The new names were clarified in 2019 in an article titled "Nomenclatural changes in Coleus and Plectranthus (Lamiaceae): a tale of more than two genera" in PhytoKeys (PhytoKeys 129 (2019) which transferred many of the Plectranthus species, including this into the genus Coleus, making the valid name of this plant Coleus barbatus. The name Coleus comes from the Greek word 'koleus', meaning a sheath, in reference to the manner in which the stamens are enclosed. We have retained the older name for now as this change gets more widely recognized so not to confuse our staff or our customers. Our stock plant came to us in 2012 from Alice Keck Park Memorial Garden in Santa Barbara, California where it was planted by long time park caretaker Carol Terry.
Information about Plectranthus barbatus displayed on this page is based on our research about it conducted in our library and gathered from reliable online sources. We include observations made of this plant as it grows in our nursery gardens and in other gardens that we have visited, as well as how the crops have performed in containers in our own nursery field. We will also incorporate comments that we receive from others about this plant when we feel it adds information and particularly welcome hearing from anyone who has any additional cultural recommendations that would aid others in growing it.