Symbolism, Imagery, Allegory
Janie has some epic hair. It seems like it's second to only Rapunzel's in its ability to drive men wild: her luscious locks are what attract Joe Starks to her in the first place.
But, because Joe is such a jealous jerkosaur, he forces Janie to wear a head-rag when in public. Her hair is just so attractive:
This business of the head-rag irked her endlessly. But Jody was set on it. Her hair was NOT going to show in the store. It didn’t seem sensible at all. That was because Joe never told Janie how jealous he was. He never told her how often he had seen the other men figuratively wallowing in it as she went about things in the store. And one night he had caught Walter standing behind and brushing the back of his hand back and forth across the loose end of her braid ever so lightly so as to enjoy the feel of it without Janie knowing what he was doing. Joe was at the back of the store and Walter didn’t see him. He felt like rushing forth with the meat knife and chopping off the offending hand. That night he ordered Janie to tie up her hair around the store. That was all. She was there in the store for him to look at, not those others. (6.31)
By making his wife bind her hair, Joe manages to constrain Janie’s femininity and stifle her identity. In an attempt to keep Janie all to himself, he suffocates her...and ends up losing her completely. When Joe dies, Janie wastes little time in burning all of the head-rags she owns. Here, the head-rag represents the constraints imposed on subjugated women by men in power.
Let those tresses fly free, Janie.