Muhammad's hair was collected as RELICS. Muhammad did not disapprove of this.
Muhammad wore his hair like the Christians and Jews:
Ibn Abbas reported that the People of the Book used to let their hair fall (on their foreheads) and the polytheists used to part them on their heads, and Allah's Messenger (may peace be upon him) liked to conform his behaviour to the People of the Book in matters in which he received no command (from God) ; so Allah's Messenger (may peace be upon him) let fall his hair upon his forehead, and then he began to part it after this. (Sahih Muslim, Number 5768, cf. Number 5769)
This hadith shows how Muhammad was influenced by the Christians and Jews.
On the other hand, we read:
Narrated Abu Huraira:
Allah's Apostle said, "The Jews and the Christians do not dye (their grey hair), so you shall do the opposite of what they do (i.e. dye your grey hair and beards)." (Sahih Al-Bukhari, Volume 4, Book 56, Number 668)Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: The Jews and the Christians do not dye (their hair), so oppose them. (Sahih Muslim, Book 024, Number 5245)
For more on the ambivalent relationship of Muhammad to Christians, see the article The Quranic View of Christians — Fellow Believers or Unbelieving Polytheists?
Shaving the hair for pilgrimage: al-Baqarah 2:196; al-Fath 48:27