He was here in his role as chairman of the International Dendrology Society, which held its annual meeting at Larnach Castle last night.
The society, dedicated to the science and study of wooded plants, had 1500 members in 50 countries.
Its annual meeting was held in a different country every second year, with Dunedin host this time.
The group of 48 travelled around the South Island, visiting Punakaiki on the West Coast and sheep stations in Geraldine before visiting the Dunedin Botanic Garden.
Its international collection was "wonderful" and Sir Richard believed it was "sad" a clampdown on foreign species entering the country had occurred.
The group will tour the North Island.