Observation Series
Growing Black Nightshade

I started drafting this piece of work on the Black Nightshade back in October 2012 but did not publish it in my website until January 2013. When I stated the draft, I thought that this plant was Solanum nigrum, commonly known as the Black Nightshade. After a more thorough research on this herb, I started to doubt its current identity. Firstly, the name Solanum nigrum was not listed in the Singapore flora checklist published in 2009. However, the name Solanum americanum was in the checklist and its appearance looked similar to my pictures of this herb. I thought I had finally got my answer until I came across an article that questioned my new found knowledge. According to this article published in 2007 [1], the herb that I saw was more likely to be Solanum nodiflorum.

photo photo While I thought that I had everthing covered, another published in 2018 [2] seemed to dispute my earlier conclusion. According to the latest article (page 61), the concepts of the taxon used in the 2007 study were different. It further elaborated that the Solanum nodiflorum studied in the 2007 publication was considered to be Solanum americanum based on the treatment of the taxon in the 2018 publication. In addition, the Solanum americanum examined in the 2007 publication was probably another Solanum species. With this new found information, I had changed the species name back to Solanum americanum.

My special interest on this herb was triggered by an email to me in May 2012 where the sender needed the herb urgently. Unfortunately, I was not able to help then. This is a rather illusive and rare herb in Singapore, where you will never know exactly where to find it. Usually, it appears on newly cleared land where the top layer of the soil has been tilled. But, it is a weak competitor in the wild. As soon as the wild plants start to occupy the land, it vanished. In April 2010, I saw a lone plant growing in a pot. It did not look likely a cultivated one but rather one from a spontaneous growth. There were some flowers but no fruits. I had no clue how the tiny seeds in the berries get dispersed.

photo photo Nearly a year later in February 2011, I found a few of this herb at a newly cleared land. There were at least 3 matured plants with flowers and fruits. The fruits were still green when I first encountered the population. When I returned a month later in March, the black berries were ready for harvest. At that time, I did not have a strong motivation to collect the berries since I had no intention to grow it. Since then, I had not seen the herb until October 2012.

This time round, it was a single plant with flowers, ripe and unripe berries located again in a newly cleared land by the edge of a forested area. Recalling that someone was anxiously looking for it in May, I was then keen to grow this herb. Before this sighting, I had approach someone who grow herbs to attempt to obtain it but was told that this herb is difficult to cultivate. He had no success yet in growing one.

Back home, I dissected 2 berries from the sample collected. The berries contained fleshy pulp where the tiny seeds were embedded. Each berry had around 32-36 tiny seeds. The dark purple colouration of the ripe berries was confined to its skin while the fleshy pulp surrounding the seeds was actually light green in colour. Since I had no idea on their survival rate, I placed 4 seeds in each small plot of the cultivation tray. A total of 48 seed were sowed. A week later, 20 seedlings appeared ----- less than half of the amount of seeds sowed.

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The seedlings seemed to be growing rather slowly. Two weeks later, there were still only 2 tiny leaves. I was worried that the seedlings might not continue to grow. They seem to be rather fragile and not much growth was seen in the past one week.

photo photo photo Meanwhile, the leftover berries had shrunk in size due to the loss of water content. I sliced opened another 2 of them. There was no more sticky pulp as it had dried up. In all, over 70 seeds were collected and kept in a sealed container for future use.

I was concern that the depth of the soil in the cultivation tray might be too shallow and the sunlight condition might not be optimal. I decided to move all the seedlings to a bigger pot located at my balcony with direct sunlight. During the move, 3 seedlings did not make it which then reduced the survival count to 17.

photo photo photo Surprisingly, more seedlings appeared in the bigger pot bringing the total number to 42, which means that only 6 out of the 48 seeds did not make it. Three weeks later on 26 October 2012, the third leaf was visible in some of the seedlings. By 31 October, some seedlings had as many as 5 leaves.

The growth of the young plants accelerated over the next few weeks which made the pot very crowded for over 40 plants. At the end of November, I started to move a few plants to some other pots but was not able to find enough space to relocate all of them. As expected, these relocated plants thrived well while those that stayed in the crowded pot looked malnourished.

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To cut the long story short, the first bundle of flower buds appeared on 22 December 2012 and eventually, the long awaited dark purplish berries arrived on 21 January 2013. In all, it took nearly 3.5 months or 14 weeks from seeds to berries. After all, it was not too difficult to grow this herb.

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Soon, 2 types of pests, namely mealybugs and white flies started to attack this herb. Both of them reside on the underside of the leaves. The mealybugs were transported around the plant by ants while the white fly colonies appear as white patches under the leaves.

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I had collected the ripe berries from my own cultivation and might continue to grow them in the future.


[1] Manoko MLK, van den Berg RG, Feron RMC, van der Weerden GM, Mariani C. AFLP markers support separation of Solanum nodiflorum from Solanum americanum sensu stricto (Solanaceae). Plant Systematics & Evolution 2007;267:1-11. | Read article |

[2] Sarkinen T, Poczai P, Barboza GE, van der Weerden GM, Baden M, Knapp S. A revision of the Old World Black Nightshades (Morelloid clade of Solanum L., Solanaceae). PhytoKeys 2018;106:1-223. | Read article |

Last updated: 28 April 2019

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