Answer:
I am wood that is neither hard straight or crooked
I am flora not fauna. I am foliage not trees. I am shrubbery not grass.
I have thirteen hearts but no body or soul.
I go in hard come out soft. Blow me hard and I’ll make a pop.
I have a small hill with seven holes. What am I?
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.