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, accounting for 95% of the total growing area. The growing area in the South Central Coast accounts for 5%. Growing and producing organic cassia products has been developed in some regions for many years and has been harvested, increased high value and income for farmers.
There are 3 harvest seasons for cassia leaves and twigs for distillation. Season 1 is from April to early July. Season 2 is from late July to mid August and lasts only 15-20 days. Season 3 from is mid-September to December.