Qatadah R.A. reports:
"I asked Anas R.A., 'Did Rasulullah (Sallallahu alaihe wasallam) dye his hair?'" He replied: "The hair of Rasulullah (Sallallahu alaihe wasallam) did not reach such a stage where one would use a dye; however Rasulullah (Sallallahu alihe wasallam) did have a few white hair on his temples, on the other hand Abu Bakr R.A. dyed his hair with Hina and Katm." (ES)
English reference (ES): Book 5, Hadith 36 (ES)
Arabic reference (ES): Book 5, Hadith 37 (ES)