It is narrated from Hazrat Abu Rimtha (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) used to dye (his hair) with henna and katam, and his blessed hair would reach up to his shoulders.
Hadith Referenceمسند احمد / مسند الشاميين / 17497
Hadith Gradingحکم دارالسلام:صحيح لغيره، وهذا إسناد ضعيف لضعف الضحاك