Curiously enough, although it’s to be found just off Plymbridge Road, Plympton it’s fairly certain that the Plym of Plymtree and the Plym of Plympton are unrelated and further that river Plym in turn takes its name from Plympton and not visa versa. It is nevertheless odd that the only “Plym” place names in Britain are in Devon and that the only other one that we haven’t mentioned is Plymstock, which like Plymtree (which is just south of Cullompton) is said to have a “plum tree” origin. Clearly both the Domesday “Plumtrei” and the medieval “Plumstok” were subsequently influenced by the name of one of the most influential centres of dark age Devon – Plympton.
There is, incidentally, a contemporary Plumtree in Nottingham, a Plumpton in Northants, a Great Plumpton and a Woodplumpton both in Lancashire and Plumsteads in London and Norfolk. There’s also a Plompton in North Yorkshire and a Plumbland in Cumbria, all with the same plum tree name origin!