Sayyiduna Abdullah (may Allah be pleased with them both) said: I heard Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) saying: Whoever braided his hair should have his head shaved, and do not imitate matting. And Sayyiduna Abdullah (may Allah be pleased with them both) said: I saw the Prophet (peace and blessings be upon him) in a state of talbid (with his hair matted).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9584