Thank you for contacting Ask Extension. There are many countries where you cannot take plants/seeds into. I would suggest that you check with the consulate of Vietnam to ensure that you can do so.

You did not state whether you want the plants to be outdoor plants, or indoor plants. So I am including the climate and weather of Vietnam: Viet Nam is located in the tropical zone. Its climate is characterized by high temperature and humidity all year round. The Northern part has more or less mainland climate. Viet Nam’s climate changes by seasons and by regions from the lowland to the highland, from North to South and from East to West. There are two major climate regions in Viet Nam: (1) Northern Viet Nam (from Hai Van Pass northwards) has a highly humid tropical monsoon climate with four distinguishable seasons (spring, summer, autumn and winter) and is influenced by the Northeast and Southeast monsoon. (2) Southern Viet Nam (from Hai Van Pass southwards) has a rather moderate tropical climate given the weak influence of monsoon and is characterized by dry and rainy seasons and warm weather all year round. The average temperature in Viet Nam varies between 21°C and 27°C and gradually increases from the North to the South. In the summer, the average temperature is 25°C (Hanoi 23°C, Hue 25°C, Ho Chi Minh City 26°C). In the winter, the temperature in the North reaches the lowest in December and January. In Northern mountainous regions like Sa Pa, Tam Dao and Hoang Lien Son, the temperature sometimes reaches 0°C with snow. The annual average rainfall stands between 1,500 mm and 2,000 mm. Air humidity is around 80%. Viet Nam is prone to natural disasters like typhoons, floods and droughts.

I believe that you would want tropical plants, that are adaptive to Zone 12-13. For a list of plants, I was not able to find one, but you might be able to get information from Vietnam National University of Agriculture https://eng.vnua.edu.vn/

Good luck and if we can be of further help, please contact us.