This is a national flower of Thailand and one of the most impressive cassias. From early spring through summer, it displays beautiful cascades of golden flowers. Cassia is a large genus with some 500 species, among which are a number of highly attractive flowering trees. To many tropical gardeners, the most beautiful is Cassia fistula. This is a medium to large tree with ovate, pointed leaflets; when these drop, usually in the dry season, masses of bright gold flower clusters appear on almost every branch. Cassia likes full sun and well-drained soil and to bloom profusely require a dry season.