Anas bin Sulayman, the freed slave of Sayyiduna Ka'b bin Ujrah (may Allah be pleased with him), said: I bear witness that I saw four or five of the Companions of the Messenger of Allah (peace and blessings be upon him) wearing clothes dyed with safflower ('usfur), among them Sayyiduna Ka'b bin Ujrah (may Allah be pleased with him).
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16381