The Picnic Room. Detail of north wall. The murals with their pattern of climbing bamboo, convolvulus and nasturtiums was painted by Princess Elizabeth (1770-1840), daughter of King George III, in c1804. Queen Charlotte's Cottage, in the Royal Botanic Gardens Kew, was built around 1771 for Queen Charlotte. It was used as a rustic retreat for the royal family, where they could enjoy picnics or take tea during the summer months.