Cassia fistula is a fast-growing tree which grows to about 10 metres in height. It is propagated by seed, which must be soaked in water for 24 hours first, to break dormancy. Seedlings planted in plastic bags survive transplant quite well, and start to bear flowers four years after planting. But why aren't there more of the trees along Bangkok's streets? Could it be because they are susceptible to insect pests and unattractive when small? Or is it because they are not as shady as other trees? Or is it simply because the national flower is not appreciated by the people in charge of beautifying Bangkok?