Hi there - never have grown ornamental grasses before, but when we put in our pond last summer I thought some would look cool near it and naturalize it -- I'm in zone 8, andplanted Fountain Grass Little Bunny, Japanese Bloodgrass, Little Nicky Silver Grass and a Pampas Grass, whose name I don't know -- they did fine 'til winter time and they've all turned brown or straw color - have they died back for the winter and should they be cut back to their roots in spring -- or have they just died????? Thanks for your help! Kathy