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Products > Plectranthus argentatus
Plectranthus argentatus - Silver Plectranthus
Image of Plectranthus argentatus
[2nd Image]
Habit and Cultural Information
Category: Perennial
Family: Lamiaceae (Labiatae) (Mints)
Origin: Australia (Australasia)
Evergreen: Yes
Flower Color: Violet
Bloomtime: Spring/Summer
Synonyms: [Coleus argnetatus, P ''Longwood Silver']
Height: 2-3 feet
Width: 4-6 feet
Exposure: Shade
Irrigation (H2O Info): Medium Water Needs
Winter Hardiness: 25-30 F
Plectranthus argentatus (Silver Plectranthus) - An evergreen perennial subshrub that is treated as an annual in frost prone climates. It is a fast growing plant to 2 to 3 feet tall by 4 to 6 feet wide with 5 inch long by 3 inch wide soft, fuzzy silver foliage and an abundance of 8 to 12 inch long spikes of reddish-purple buds that open to very pale violet (almost white) flowers summer to fall (August-October). The flowers are nice, but the showiest aspect of this plant is its foliage.

Plant in full sun to partial shade - plants seem lusher with some shade and it can even take pretty deep shade. This plant is reasonably drought-resistant in good soil when mulched but looks best if given regular to occasional irrigation and tolerates moist soils. Hardy and evergreen to 25 F; has resprouted from the ground after temperatures just below 20 F. This plant can be damaged by strong winds or by traffic along paths due to brittle branches and can get a little scraggly with age, so prune occasionally to keep tight and promote new growth - cutting back hard every couple years in late winter to early spring can rejuvenate the plant and keep it quite handsome.

This plant is native to south-western Queensland and north-eastern New South Wales in Australia. In some nomenclatural data bases this plant has been reclassified as a Coleus species, Coleus argentatus, while other sources still list Plectranthus argentatus as the accepted name. Plants in these two genera have been reclassified many times since the genera were both described in the late 18th century, Plectranthus in 1788 and Coleus in 1790.

The name for the genus Plectranthus 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 comes from the Latin word 'argent' meaning "silver" and the adjectival suffix 'atus' meaning "possessing" or "a likeness" for the leaves being a silver-like color. Our plants came from Rick Dark of Longwood Gardens in 1991 and appear to be the same as what is sold by some nurseries as 'Longwood Silver'.

In 2019 Dr. Alan J. Paton, head of collections at the Royal Botanic Garden Kew, did a thorough reclassification of Coleus, Plectranthus and other closely related plants in the mint family (Paton AJ, Mwanyambo M, Govaerts RHA, Smitha K, Suddee S, Phillipson PB, Wilson TC, Forster PI, Culham A (2019) "Nomenclatural changes in Coleus and Plectranthus (Lamiaceae): a tale of more than two genera" in PhytoKeys 129: 1-158. In this article they separate these two genera by how the pedicel attaches to the calyx and whether the corolla lobes are of equal length. 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 argentatus. 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 argentatus 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.