Pampas grass is a fine, fine spreading
plant that can grow and multiply under many conditions. I have it in my clay soil and it's fine. I would not put it in a
flower bed, as it can get use up a lot of space quickly.
Leave it up during the cold months as winter interest, but be sure to cut it down to about four inches tall in late winter/early
spring, so that sunshine can fall on the new growth. otherwise, it'll develop a hollow place in the center, which can collapse and ruin the billowing pillar effect.