crotalaria retusa

I saw this (left) many moons ago at the Hortpark. Then I saw them being planted at various public spaces including the entrance to Dairy Farm nature reserve. When I saw it on sale at World Farm, I grabbed a pot.

Then just weeks ago, I spotted another specimen growing wildly along the roadside near the Biopolis park. So I uprooted that and took it home. However, I noticed that the one I picked up is different from the one I bought from World Farm. Though the flowers and leaves look similar, the one from Biopolis (pictured left) looks more like a weed whereas the other (pictured right) is a lot more ornamental. Other notable differences included the size of the leaves and the fact that the yellow petals of the one from Biopolis had fine purple lines. Perhaps one is a species while the other is a hybrid?

Commonly referred to as Rattleweed or Rattlebox, Crotalaria retusa is an annual herb and member of the bean family Fabaceae). It is effective as an ornamental plant when planted en masse as the bright yellow flowers which are borne on an erect spike makes this a very cheerful plant, particularly when planted as a border.

Cultivation of this plant is relatively easy. The seeds can be collected from the flower pods once they are dry (brown/black). As it's common name suggests, the seeds within the pod will rattle, particularly when the wind blows. Another interesting feature about this plant is the fact that it is known to be a butterfly host plant, particularly that of the pea blue butterfly (Lampides boeticus).