Yes, because it is a proper noun. It should be--- Grey Sage Bush.
A herb
Zane Grey wrote Riders of the Purple Sage.
Grey
Mule Deer
You can add dried sage to your stuffing recipe for extra flavor.
Mule Deer
The Rainbow Trail (Zane Grey)
The cast of The Sage-Brush Phrenologist - 1911 includes: Pauline Bush
Sage grouse eat sage. Its their primary source of food in the winter.
2 monthes
Sage green is a grayish, soft green. If you Google search images the word sage you'll see the plant it's named after.
You just have to find them. Sage 1 - Dreamyard, in a previously inaccessible area, Sage 2 - Relic Castle, Sage 3 - Chargestone Cave, third level, Sage 4 - Cold Storage, inside a container, Sage 5 - Route 17, on the westernmost island, Sage 6 - Route 14, you need 'Waterfall' to reach him, Ghetsis - Captured at the end of the main plot, but escaped and can't be found (until Pokemon Grey, perhaps).