Answer:
Plant whose name sounds like a dish full of dairy spread.
What measures out time. Until in time all is smashed to it?
The more you take, the more you leave behind.
It happens when something has been cut with H2O.
What is that over the head and under the hat?
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.