Scottish. The occurrence of Primrose as a male name is very rare but is occasionally found in Scottish records. It is likely that this male name originated with the surname which was derived from estates in Dunfermline, Scotland and family name of the Earls of Rosebery.
One correspondent [HG] sent the following note on the Parish Records of Fordyce, Banffshire:
"A witness on 11 November 1760 was described as 'Primrose Robertson son to Mr James Robertson Jnr merchant in Portsoy'." The boy, Primrose, was 5 at the time.
Another correspondent [GB] has noted in the 1851 Census three men living in Portsoy in Fordyce parish [now in Aberdeenshire but then in Banffshire, Scotland] each with the forename Primrose. GB has also found a number of other occurrences were found in the 1881 Census of Scotland, in Fordyce [not the same as any of the above], Aberdeen and Stirling and in several graveyard inscriptions.
The male use predates the female use of Primrose which was introduced by the Victorians along with many other flower names.