Rupp was made deacon on 28 May 1899 and ordained priest on 2 June 1901. He began recording his botanical observations and specimens in 1892; from 1899 made 'a census of the native plants' of his parishes.
Rupp was consecrated deacon on 28 May 1899 and ordained priest on 2 June 1901. He started documenting his botanical observations and specimens in 1892; subsequently, he conducted an inventory of the local flora in his pastoral areas.