Iris giganticaerulea (or 'Giant blue iris') is a species of iris, it is also in the subgenus of Limniris and in the Series Hexagonae. It is a rhizomatous perennial, from northern America. It has long bright green leaves, very tall stems, 1-2 musky fragrant flowers, in a range of blue shades, from pale blue, to lavender blue, to bright blue, to dark blue, and to violet blue. Rarely, there is a white form.