I always heard it as:
Blood! Blood! Blood makes the grass grow.
Grass! Grass! Grass makes the trees grow.
Trees! Trees! Trees make the fire blow.
Fire! Fire! Fire makes the iron glow.
Iron! Iron! Iron makes the blood flow.
Blood! Blood....
Of course this has nothing on my personal battlecry, which guarantees to make the enemy pause and contemplate the result of being defeated:
"Eat the wounded, and rape the dead!"
