This is Mugwort, a plant which is used in a number of ways in traditional Chinese medicine to promote health and treat illness.  It is used to kill harmful bacteria and fungi. Mugwort oil is also used to repel insects.

Calamus is also hung on doorways at Dragon Boat Festival.  It smells sweet and the plant is also used in traditional Chinese medicine for a number of illnesses.

At Dragon Boat Festival, many households are decorated with these two herbs.  Can you think of a time of a festival when people in Britain bring greenery into the house to decorate and perfume the rooms?