Answer:
Glittering points that downward thrust. Sparkling spears that never rust.
What has roots that nobody sees, and is taller than trees. Up, up it goes, and yet it never grows.
A house with two occupants, sometimes one, rarely three. Break the walls, eat the boarders, then throw away me.
Who spends the day at the window, goes to the table for meals. And hides at night?
As soft as silk, as white as milk, as bitter as gall, a thick green wall, and a green coat covers me all.
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?