Coleus (Solenostemon scutellarioides syn. Coleus × hybrida) are one of those annuals that are so widely grown that gardeners today tend to take them for granted, but surprisingly, they’re relative newcomers to Western gardens—though few plants have gone in and out of fashion as frequently as coleus have done.
Providing guaranteed colour all summer long in every shade except blue, coleus are treasured for their brilliantly patterned leaves rather than for their flowers, which are apt to detract from the overall beauty and symmetry of the plant. Historically, gardeners have relied on coleus for dark, shady corners where little else would grow, but during the past 10 years, coleus have moved out of the shadows and into the limelight, with most modern cultivars requiring a couple of hours of sun each day for their leaves to attain optimum colour saturation. Available in a variety of sizes, growth habits and leaf shapes, with colour combos that range from subtle to shocking, there is definitely a coleus to suit every taste.
Discovery of the coleus
German-Dutch botanist and plant hunter Carl Ludwig von Blume (1796-1862) is credited with discovering coleus on one of his many trips to Java, then part of the Dutch East Indies. It was introduced to Britain in 1853 under the name Coleus blumei, or flame nettle, and by the 1880s was a common Victorian houseplant on both sides of the pond. Having fallen out of favour by the end of the First World War, after the Second World War new, leafier varieties were developed, leading to its first comeback. In the 1970s, coleus again became popular during the houseplant craze, but it wasn’t until the explosion of breeding work conducted in the 1990s that it re-entered the mainstream.
An interesting attribute
Coleus have another intriguing attribute: they have a predisposition to send out “sports,” naturally occurring genetic mutations whereby a particular branch or section of the plant looks different from the rest. A good example of “sporting” is almost any variegated plant you can name—virtually all of them arose as naturally occurring mutations. But it doesn’t end there; coleus are also prone to “reversion,” whereby a section of plant reverts to a form found somewhere in its genetic past; a good example of this is when a shrub like ‘Emerald Gaiety’ euonymus suddenly sends out a solid green shoot rather than a variegated one. Given the complicated and largely undocumented ancestry of modern coleus, it’s impossible to tell if new forms are sports or reversions, but for the sake of simplicity, all such growth is referred to as a “sport.”
Inset photo: 'Mars' and main image 'Swiss Sunshine'