Make the new biome color grass a unique block

The new Poplar tree biome has some unique grass but that is just a biome color. Its not a variant of green but sort of orange. Make this a unique block. The color an be explained by the rust disease grass can have. I think that's a great name too, rusty grass. As it is a fungus like disease it can work as mycelium so it is just a re skin for a existing block. We will miss the smooth transition but it would fit the same like podzel does.