Plectranthus lanuginosus (Downy Spur-Flower) - An herbaceous low growing and dense subshrub to 10 to 18 inches tall by 3 feet wide with soft slightly fuzzy dark green rounded ovate leaves. From early fall through late winter appear the electric blue flowers on 4- to 6-inch-tall inflorescences.
Plant in a well-drained soil in full coastal sun to bright shade and irrigate occasionally to infrequently - taller with more regular irrigation and particularly drought tolerant in the shade garden. Hardy to 25° F. A light trim after flowering will keep this plant neater looking. A nice container or hanging basket plant and in the ground will grow as a solid weed smothering groundcover with showy blue flowers and, unlike some other Plectranthus species, this one does not have foliage with a strong aroma.
This plant was first collected in Somalia but known also in the highlands of Ethiopia, Yemen and Eritrea and naturalized in east Africa as far south as Zimbabwe. It was first described by George Bentham in 1848 as Coleus lanuginosus in Augustin Pyramus de Candolle's Prodomus Vol. XII. It has also sometimes incorrectly been identified as Plectranthus barbatus, a much larger upright shrubby plant that we also grow. This likely because of a previous name for Plectranthus lanuginosa was Coleus barbatus var. schimperi. The name for the genus comes from the Greek words 'plektron' meaning a "spur" and 'anthos' meaning "flower" in reference to the spur that is found at the base of the corolla tube of the type species Plectranthus fruticosus. The specific epithet from the Latin word 'lanugo' meaning "covered with down" or "fine soft hair" from the Latin root word 'lana' meaning wool. 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 lanuginosus. 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.
This information about Plectranthus lanuginosus displayed is based on research conducted in our horticultural library and from reliable online resources. We also will relate observations made about it as it grows in our nursery gardens and other gardens we have visited, as well how the crops have performed in containers in our nursery field. We will also incorporate comments that we receive from others and we welcome hearing from anyone with additional information, particularly if they can share any cultural information that would aid others in growing it.
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