Vietnam is the world's third-largest producer and exporter of cassia products. Cassia is grown on a large scale in the mountainous areas of Northwest Vietnam, about 200,000 ha (1,500 km2), accounting for 95% of the total growing area. The growing area in the South Central Coast accounts for 5%. Growing cassia is currently a livelihood for hundreds of thousands of households in remote provinces, and at the same time contributes to the socio-economic development of many localities in Vietnam.
Harvest time of leaves, twigs, and bark for distillation is from April to December