Isto é Zahrah the Windseeker, by Nnedi Okorafor (then Okorafor-Mbachu).
The plant hair is clear from the cover.
The fact that she can fly is in the title: she's a Windseeker:
My old old grandmother once told me that a few of these dada-born
folks were born with the ability to fly. Windseekers, she used to call
them. But she also told me that there were little blue men three
apples high who lived in the mushrooms that grew in our backyard. I
know a friend of a friend who knows two dada-born folks. He said
neither of these individuals has ever left the ground without any
help. So maybe my grandmother is not so reliable, but you can trust me
when I say that this year’s most stylish will be wearing dada
extensions.
Zahrah the Windseeker
And the rest of what you mention is essentially the book blurb:
Zahrah, a timid thirteen-year-old girl, undertakes a dangerous quest
into the Forbidden Greeny Jungle to seek the antidote for her best
friend after he is bitten by a snake, and finds knowledge, courage,
and hidden powers along the way
Zahrah the Windseeker