Provided are methods for generating iris plants having flowers expressing red, red/orange, or orange/red color, previously non-existing in this plant genus, thereby expanding the color palette of, and generating new and exciting varieties of, ornamental plants. These methods employ capsanthin-capsorubin synthase-encoding nucleotide sequences, and are also applicable to other genera, species, cultivars, and varieties of ornamental plants in which red, red/orange, or orange/red flowers have been desired. The nucleotide sequences and methods disclosed herein can be applied to genera, species, cultivars, and varieties of ornamental plants that produce yellow pigments, or yellow/orange flowers, but no red flowers, to produce novel red-, red/orange, or orange/red-flowering plants. Plants normally producing the yellow pigments antheraxanthin and/or violaxanthin, or yellow or yellow/orange flowers, are preferred for such modification using the presently disclosed, or similar, methods employing capsanthin-capsorubin synthase-encoding nucleotide sequences.
