What would be ugly in a garden constitutes beauty in a mountain.

The remark contrasts two aesthetic regimes: the cultivated garden, where beauty is associated with order, proportion, and careful design, and the mountain, where beauty often arises from irregularity, roughness, and even apparent disorder. Hugo’s point is that standards of taste are context-dependent: what seems like a flaw in one setting can be precisely what gives another setting its grandeur. Read more broadly, it suggests a Romantic valuation of the sublime in nature—wildness, scale, and rugged forms—over the controlled prettiness of artifice, and it cautions against applying a single measure of “beauty” to all environments or experiences.