The genus Iris encompasses hundreds of species known for their elaborate and showy flowers. The name “Iris” is derived from the Greek word for “rainbow,” referencing the goddess Iris, who personified the rainbow and served as a messenger. This mythological association relates directly to the flower’s reputation for having one of the broadest and most diverse color spectrums found in the plant kingdom. Cultivated varieties of Irises have been popular in gardens for millennia, dating back to at least 1469 B.C. in Egypt.
The Core Color Palette
Solid, or self, colors are those where the upright petals (standards) and the downward-falling petals (falls) are the same hue. Blues and purples are perhaps the most common and historically significant colors, ranging from the palest icy blue and lavender to deep, saturated violet and indigo. The prevalence of these shades is due to the plant’s pigment biochemistry, which is heavily biased toward delphinidin-derived anthocyanins.
The yellow and gold range is extensive, spanning from soft, pale lemon and cream shades to vibrant golden yellow and deep, almost orange-yellow tones. Pure whites represent another important color class, offering a clean, crisp appearance, though some white varieties feature a colored “beard” or slight veining. Pinks are regularly available, generally presenting as delicate salmon, peach, or apricot tones, since a true, bubblegum-pink shade is much more difficult to achieve in Irises. These solid colors provide the primary building blocks for the more complex patterns seen in modern hybridization.
Unique and Complex Patterns
The Iris flower showcases specialized patterns that create visual complexity through the distribution of pigments. Bicolors and bitones are common terms used to describe flowers where the standards and falls are distinctly different colors or different shades of the same color, respectively. A specific type of bicolor is the Amoena pattern, characterized by white or near-white standards paired with falls of any other color.
The Plicata pattern features a lighter ground color, often white or yellow, overlaid with a stippled, stitched, or dotted edge of a darker color along the petals. The Variegata pattern is a striking bicolor defined by yellow or gold standards combined with falls that are a contrasting red, maroon, or brown. Luminata is a pattern where color is washed over a white or yellow base, giving the appearance of an inner glow with unpigmented veining. Rare broken colors appear as random streaks, splashes, or splotches across the petals.
The Elusive Hues
Certain hues remain genetically out of reach for hybridizers. The so-called “black” Irises are not truly black but are instead very deep, highly saturated shades of purple, violet, or velvety dark blue. These ‘near-black’ colors absorb so much light that they create an optical illusion of blackness, especially in certain lighting conditions.
A genetically true scarlet or fire-engine red Iris is also currently impossible to achieve. While breeders have developed flowers in shades of rust, brick-red, deep maroon, and orange-red, the necessary pelargonidin-derived anthocyanins for a pure red are not metabolically produced by the plant. Similarly, a solid, foliage-green flower does not exist; Irises described as green actually display chartreuse, olive, or yellow-green undertones.