Purple Hyacinth Beans

The hyacinth bean is not a common legume in Singapore as I haven’t seen before its fresh pods being sold in our local wet markets. I got to know about this edible bean came from the books that I read written about vegetable gardening in the tropics.

As far as I can remember, I chanced upon the seeds of the purple podded version of the hyacinth bean at Known You Seeds many years ago when I was still a Primary School kid. The seeds of this legume are not readily available and the green podded ones are the type that is usually used for food. The purple podded ones are grown more for their ornamental value but they are still edible. At that time, I cannot grow this bean due tot he lack of space as I lived in a highrise apartment.

Two years ago when I got the community garden started and driven by my eagerness to grow things in the outdoors for the first time, I rushed to buy a packet of hyacinth seeds to grow. It was only then I had ample space and sufficient sunlight to grow this sprawling vine because my knowledge of the hyacinth bean was that it can become a woody, vigorous perennial in the tropics and hence is able to grow up to more than 10 m!

The seeds, I found, were notoriously difficult to germinate. Not only those from Known You Seeds but also seeds from other sources. Maybe it was the age of the seeds when I got them. I have also noticed that seeds which were fatter and full tend to germinate more readily whereas those that appeared shrunken tend to fail. Like most legume seedlings, the plants looked weak and fragile when they first started. Below is a picture that was taken when the vines were about almost a month old.

For those who of us who have grown beans before, we all know that after a while, the growth rate speeds up and the vines would start to take over the trellis at a rapid pace. The foliage of this plant was not highly ornamental because from far, they look like those that could be found on any regular bean plant. Below is a picture that was taken two months later. In the picture, the hyacinth bean vines are hidden somewhere near to the back of the bamboo pole trellis that also has some bittergourd vines growing on it.

A month or two passed, the purple hyacinth bean plants I sown about four months ago started to flower. Similar to what had been described on the seed packet as well as what I have read, the flowers the vines produced were highly ornamental. They were perhaps one of the most beautiful legumes I have ever grown! The flowers grew on a branched flower spray that was coloured purple too. The flowers were of a lighter purple colour, violet to be more exact and several were open on a day.

The earlier flowers after they had been pollinated would start to set fruit and the young pods that were formed are coloured a brilliant purple. The young pods developed alongside with more flowers that gradually open along the spray, as shown in the picture above. When all the flowers finally fall off, the entire spray would be laden with purple hyacinth bean pods that looked so fat and full and of course, too attractive to be picked for the dinner table!

Like many typical Singaporeans, most of my community gardeners were adverse towards such ‘alien-looking’ vegetables and no one dared to take the challenge to take some bean pods home for the cooking pot. I told my mum to boil the shelled beans from the immature bean pods in soup and they tasted just fine – no beany flavour that have been described by some sources.

The young immature hyacinth bean pods can be eaten like snow peas when they are cooked. Immature hyacinth beans will have seeds that are still soft and green as shown in the picture above. The dried mature seeds of this legume can also be consumed but must be done with caution as these contain cyanogenic glucosides and the cooking water must be discarded after boiling the beans. You should only consume these mature seeds after boiling them twice or more times!

In contrast to the seeds found in the still immature, purple-coloured pods, mature hyacinth beans have seeds that are dark and the covering of the pods have all turned brown as shown in the picture above.