Bixa orellana – A beautiful shrub that bears fruits that yield an important food dye

In the past, Bixa orellana used to be a very popular shrub that was commonly planted in Singapore’s streetscape. Now it is seldom seen. Native to Central and South America, Bixa orellana is a woody shrub that can grow into a tree if it is left alone and as a plant, it is not very remarkable and looks like any other green shrub. What makes this plant decorative are its flowers and fruits.

When I was younger as a kid, I have always asked my parents whether the heart-shaped, reddish fruits that are covered with fine bristles borne by Bixa orellana were rambutans. I have always wanted to pick one fruit to take a closer look at it but my parents, like most parents at that time, would discourage me from even attempting to touch it, because they thought the fruits are poisonous! There is another less commonly seen version of Bixa orellana that bears fruits with a yellow rind.

Although the fruit is not edible, the seeds found inside the dried fruit capsules of Bixa orellana have a very important use. When they are totally dry, the fruits of Bixa orellana become hard and brown and they split sideways to reveal a cluster of seeds and this where the edible food dye called “annatto” is derived from. This natural yellow colouring, called bixin, can be extracted by stirring the seeds in water. It is used to color food products, such as cheese, fish, and salad oil.

The flowers of Bixa orellana are quite ornamental, although not as strikingly as its fruits, probably due to their smaller size and shorter lifespan. Pink in colour and resembling somewhat like peach blossoms, the flowers of Bixa orellana are borne as a cluster at the tip of the growing point. This is a growth characteristic that we need to learn about the plant that is important if one wants to grow a nice Bixa orellana specimen. If one desires a profusion of fruits and flowers, we need to prune Bixa orellana in such a way so that a shrub can develop multiple branches so that more flowers and subsequently, fruits can be produced. 

Almost a year back, I managed to purchase two Bixa orellana from a local nursery. This shrub seems to be quite difficult to find on sale locally. They have been planted in a relatively open location on one side of my community garden and the two plants receive direct sunshine during the day.

However, the location can get quite wet during the rainy season and for shrubs, I do sometimes worry whether they will succumb to the complications caused by prolonged wet feet. They have been growing there for quite some time already and so far, they seem fine. Once in a while, I throw a handful of slow-release fertiliser around the root zone. When they are established, Bixa orellana seems to be able to take some degree of drought. My plants seem quite happy if they are watered on alternate days even during the hot and dry season.

Bixa orellana can be propagated by seed but I have always regarded growing flowering shrubs from seeds a painful experience due to the lengthly time one has to wait for the plant to mature and then flower. That is really a test of one’s patience. If stem-cuttings can be taken, I thought that would be a more prefered choice and fortunately, the stems of Bixa orellana can be easily rooted. As woody shrubs, I think Bixa orellana can also be propagated via marcotting.

I can still vividly remember when I first bought my Bixa orellana, I got a rude shock when I was transplanting them into the ground. The root ball of both plants which was revealed after the loose soil fell off was really small for a large shrub which I was handling with. I reckon they were newly propagated nursery stock that were recently being put on sale.