Tupac is the rose. He is saying that when he had nothing to begin with before he started his music. When he had nothing no one cared. This piece is also saying that anything can happen even if no one cares about what your doing at that very moment!
Did you hear about the rose that grew from a crack
in the concrete
Proving nature's law is wrong it learned 2 walk
without having feet
Funny it seems, but by keeping its dreams,
it learned 2 breathe fresh air
Long live the rose that grew from concrete
when no one else even cared!