Answer:
I hide but my head is outside.
Grows from the ground, bushes and grass, leaves of yellow, red and brow, unruly plants, get the axe, trim the hedge back down.
The more of it there is, the less you see.
Many hear me, but no one sees me, and I only speak when spoken to
What relies on columns but isn't a house, and asks for help but can't speak itself?
When is it bad luck to see a black cat?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?