[3] He bought Highdown Gardens, an estate near Worthing, Sussex, in 1909 and lived there for the remainder of his life.
He was present at Paris Peace Conference, 1919, where he supported the British prime minister David Lloyd George as private secretary.
[5] Stern collected plants between 1900 and 1910, working with Reginald Farrer, Frank Ludlow, Joseph Rock, and George Sherriff.
[3] In 1914 he financially participated in a plant collecting expedition by Farrer and William Purdom to Yunnan and Kansu.
[9] Herbarium specimens of some of the plants from Highdown Gardens are kept at the Natural History Museum, London.