What color should be seen Where our fathers' homes have been But their own immortal Green?

The lines pose a rhetorical question about what “color” ought to mark places associated with one’s forebears. “Immortal Green” suggests a symbolic hue tied to memory, continuity, and renewal—green as the color of living growth, enduring landscape, or an emblem (possibly political or communal) that outlasts individual lives. The speaker implies that ancestral homes and the ground they stood on should be visually and emotionally claimed by this green, as if heritage leaves a lasting tint on the land. The tone is elegiac but also declarative: the fathers are gone, yet their presence persists through a shared symbol that cannot fade.