When I went all grain, my beers tasted like grass, and green apples. They still taste that way on occasion.
Some of it depends on your water. My water grabs every taste from the hops and grain. Even the the ones you dont want, such as the grass taste. Also it can depend on how the grains were stored.
The green apple taste went away when I left the beer in the primary for a month so the yeast can clean up after it selves.
The grass taste will go away in time.