The Ratchaphruek (Cassia fistula L.) or Golden Shower Tree is the national flower of Thailand. It is also named "Khun" or "Chaiyaphruek". The reason that the Ratchaphruek is used to symbolize the nation lies in color: its yellow blossoms match the yellow of Buddhism; furthermore, the Thai people regard yellow as the color of the King as well. Moreover, all golden shower trees bloom at the same time; this unity in flowering is felt to reflect the unity and identity of Thais.

The event was located in 80 hectares of land at the Royal Agricultural Research Center in Mae Hia sub-district, Mueang district, Chiang Mai Province in northern Thailand. The 92 days of the expo featured 30 international gardens reflecting nations such as Japan, South Korea, Belgium, Netherlands, South Africa, and Canada; more than 2.5 million trees of 2,200 species of tropical plants and flowers are presented to the world in this exhibition. The AIPH, the Association of International Horticultural Producers, gave this expo A1 status, its highest level; such an exhibition occurs only once a year throughout the world. In addition, a host country can only hold one such exhibition once a decade.