I pounced upon something that I have never witnessed before. I have grown the Indian borage plant (Plectranthus amboinicus), both the all green version as well as the variegated one, but I have never seen its flower with my own eyes before. My observation was also echoed in PROSEA’s entry on the Plectranthus – Plectranthus amboinicus rarely flowers in Malesia. It is a popular herb grown by many Singaporeans for the use as a treatment for coughs and sore throats.
I visited Oh Chin Huat Hydroponic Farm over the weekend and at their medicinal herb garden, I caught a glimspe of the flowers borne by the Indian borage. Numerous light blue flowers were borne on a terminal spike. Individual flowers were small and has a distinct lip with four yellow spots. They are reminiscent of those produced by the so-called colourful foliage coleus plant which has now been reclassified under the new genus Solenostemon.
This brings us to the three closely related genera in the mint family, Lamiaceae – Plectranthus, Coleus and Solenostemon. At present, there is still much disagreement about generic delimitation in these three genera.
In my favourite reference PROSEA, under the entry for Plectranthus, it was stated that, strictly speaking, Coleus is often considered as distinct from Plectranthus, on the basis of the fused bases of the calyx filaments. However, this is a variable and unreliable character. It is not unusual to see Coleus is still considered as a synonym of Plectranthus. In some herb books, one will see the Indian borage known as Coleus amboinicus.
Those colourful foliage plants now classified under the genus Solenostemon have calyx segments that are about equal whereas Plectranthus species have a a distinctly 2-lipped calyx.
Sounds confusing, isn’t it? Frankly, I have taken the above distinctions for granted as a gardener for a long time as I have never went into looking at the plants closely. It is perhaps time that I go pick some flowers borne by these three genera so as to be able to take a closer look at them.
I have just put up the 2 feature articles on the Green Culture Singapore website for Oct 07. One was written by a fellow member of the forum, whose name is Albert, where he covered his own experience of growing moth orchids at his home’s balcony. The other one was written on the Indian Borage, penned by me. It was written to clarify the confusion Singaporeans have for this herb. It is not a mint!
Albert’s Phalaenopsis Growing Experience
Albert, a member of the Green Culture Singapore discussion forum, focusses his efforts on the cultivation of Phalaenopsis orchids. He feels that, Phalaenopsis, with their broad leaves and elegant sprays of colourful blooms, are far more captivating than any other genera of orchids he has grown. Not only does he enjoy the beauty of these orchids, he likes to research, experiment with and learn all about them. In this article, Albert shares with readers how his Phalaenopsis plants are grown in relation to how some factors and constraints posed his home’s balcony where his plants are currently situated.
I am not a Mint!
In Singapore, the Indian Borage is often mistakened as a type of mint. To make things worse, a rough search using the Internet search engine will yield has several confusing common names. Botanically, the Indian Borage is known as Plectranthus amboinicus and is a member of Lamiaceae and this herb is famed for its use as a cough remedy. Read on to find out how to grow this plant!