Cosmos sulphureus 

Our handmade watercolours are all available on our Etsy store

How to use: Wet surface of pan. Gently scrub the surface. 

Storage: Store in a cool, dry place, out of direct sunlight. Ensure the pan is dried out before keeping. Even though we boil our inks with natural preservatives, there is still a chance of mold growing. In case that happens, just scrap off the moldy part and you should still be able to continue using the colours.

Made with Cosmos watercolour and iron modifier. 

The Cosmos “Sulphur Orange” watercolour is released as part of our Tropical Palette! 

The Sulphur Cosmos is an annual herb (they only have a lifespan of one year) native to South America. In her relatively short lifespan of a year, the plants produce many vibrant blooms of orange and yellow flowers, forming this gorgeous backdrop against other plants on our rooftop garden. 

Bouquet of Cosmos flowers.

They thrive well in dry, poor soils; once a few of them start growing and flourishing, we barely had to do much except to prune them from the top slightly to prevent the strong winds from toppling them over. The plant self-seeds very efficiently, despite her short lifespan, she makes sure that the soil is “well-seeded” before dying off to allow space for the next generation to grow.  

It’s a super fuss-free plant to grow in the tropics, well attuned to the year-round heat and humidity. Perhaps this is why these flowers can be frequently spotted in our backyard gardens! Not to mention the flowers are also edible – they make great decoration for bakes! She is also a pollinator plant that attracts many helpful bee friends for our garden…

Hello little bee pollinator!

Her edible flowers were already sources of yellow / orange dyes among the pre-Columbian civilizations of Central and South America. In southern Africa, they were adopted as a popular yellow dye by European settlers for domestic textile production and are still used by dyers using natural dyes as a hobby or for textile crafts. Not only used for her aesthetics, her leaves and seeds have been documented as a traditional malaria treatment in Brazil. 

Having read about the usage as a dye, we tried out the lake pigmentation method on the orange dye solution after soaking the flowers in hot water. Having worked with so many bright flowers which gave pale brown/gray lake pigments, we were wonderfully surprised to see the pigments maintain the bright orange shade of the flowers.

Dark orange lake pigments from the cosmos.

What are the pigments responsible for the cosmos’ vibrant orange? 

Whilst most yellow to orange flowers of Asteraceae (sunflower) family which the Cosmos sp. belong  to contain mostly carotenoids (the same group of pigments that give carrots their orange), the primary pigments in Cosmos sulphureus are flavonoids, namely butein and coreopsinFlavonoids, unlike carotenoids, are readily soluble in water because of their molecular structure. This explains why we were able to extract her colours easily by boiling in water, when we were unable to with the carotenoid-dominant annatto seeds. 

Molecular structure of Coreopsin. The -OH alcohol groups make them soluble in water.

Our Cosmos watercolours are available for sale at our Etsy shop.

Links to References: 

1.  Cosmos sulphureus (sulphur cosmos). (2019). CABI. https://www.cabi.org/isc/datasheet/110395#tosummaryOfInvasiveness

2. Botsaris, A. S. (2007). Plants used traditionally to treat malaria in Brazil: the archives of Flora Medicinal. Journal of Ethnobiology and Ethnomedicine, 3(1), 1. https://doi.org/10.1186/1746-4269-3-18

3. Extraction, optimisation and dyeing of silk yarn using natural dye from cosmos sp. (2017). International Journal of Development Research, 1. https://1library.net/document/q76115ky-extraction-optimisation-dyeing-silk-yarn-using-natural-cosmos.html