The cassia tree, more popularly known as the golden shower tree, is native to tropical Asia. It is a flowering plant belonging to the family Fabaceae, and botanically known as Cassia fistula L.
It has a rich background of being used in the preparation of Ayurvedic medicines. In Sanskrit, it is referred to as aragvadha, which literally means disease killer. The tree and its parts are used for many medicinal purposes. It also has the honor of being declared as the national tree of Thailand.
The cassia tree is tolerant of most soils, but prefers moist and well drained ones. It requires full sunlight for blooming, and the flower colors to come true. The tree is primarily propagated through seeds and graft methods. Before germinating the cassia seed, a word on how to go about it.
A dried seed is generally dormant, and the seed coat is impervious to water and gases required to kick start the germination process. A cassia seed has a very hard coat that needs to be broken for germination, hence, it is essential that the seed coat be altered physically.
Nature has its own way of doing so, like it being passed through the digestive tract of various animals, or some microbial activities, but that takes quite a bit if time. So, most commercial growers resort to scarification; a process of breaking or scratching the seed coat to allow penetration of water and gases.
So if you have collected healthy seeds, soak them up in concentrated sulfuric acid for a couple of hours. The soaking duration depends upon the species. Wash the seed thoroughly, and soak in water for 24 hours before sowing. This 24-hour sowing will break the inner dormancy. Sow in a pot/s using the sowing medium.