The Wizards of Middle-Earth...

[Selmo]

Originally Posted by Celegost

This is odd because the Hobbits could only have known of one Wizard who smoked pipe-weed (Gandalf), because even though Saruman did as well, he had it transported to Isengard secretly.

Concerning pipe-weed was added to the Red Book after Frodo's time.
Presumably, the writer was familliar with Merry and Pippin's accounts of finding Saruman's stash of pipe-weed at Orthanc.