As Saru pointed out, Samson's hair wasn't the source of his strength. To clarify further, God was the source, and Samson's strength was from him. When Samson's hair was cut, he was no longer the Lord's Nazarene, and the Lord no longer blessed him with strength. [noted -ed]
In the description of this name it states that Samson's hair was the source of his power. Technically this is an inaccurate statement; God was the source of his strength, his hair was merely a sign of his Nazarite vow.