The name of the Iris genus, which contains over 300 accepted species, comes from the Greek word for rainbow, reflecting the flower’s wide color range. This botanical family offers one of the most extensive color palettes found in the plant kingdom, making it a favorite of hybridizers. The unique structure of the flower, with its three upright petals called standards and three downward-curving sepals called falls, provides a complex canvas for color expression. Understanding iris colors involves looking at both single-hued varieties and intricate patterns.
The Comprehensive Spectrum of Iris Colors
Solid-colored irises, known as “selfs,” cover nearly every shade imaginable. Color production is controlled by two major pigment groups: anthocyanins, which create blues, purples, pinks, and reds; and carotenoids, which create yellows and oranges.
True blue is a relatively rare color in flowers, but irises express it deeply, ranging from pale sky-blue to near-navy hues. The violet and purple spectrum is the most common, with anthocyanin pigments creating shades from light lavender to rich purple. Yellows and golds, produced by carotenoids, are equally represented, appearing in shades from creamy lemon to deep, saturated gold.
The spectrum also includes whites, which lack both anthocyanin and carotenoid pigments, resulting in pure white or creamy tones. Pinks range from soft pastels to deeper rose shades. Oranges often carry a hint of yellow, achieving shades of tangerine and salmon through concentrated carotenoid pigments.
Specialized Color Patterns and Combinations
Beyond the solid-colored selfs, irises are distinguished by specialized patterns that combine different colors on the standards and falls. The term “bicolor” describes flowers where the standards and falls are distinctly different colors, while “bitone” refers to flowers where the standards and falls are different shades of the same color. An “amoena” is a specific bicolor characterized by white or near-white standards paired with falls of any other color.
The “plicata” pattern features a light ground color, typically white or yellow, that is stippled or edged in a contrasting color like blue or violet. This stitching effect creates a delicate, patterned rim around the petals. The “variegata” pattern is a classic bicolor where the standards are yellow or gold, and the falls are a contrasting red, maroon, or brown.
The “luminata” pattern presents as a white or yellow ground color washed over with a second color, often leaving the veins and a center area lighter, which gives the flower a glowing appearance. Additionally, the small, fuzzy line on the falls of bearded irises, known as the “beard,” often provides a contrasting element, such as a bright orange or yellow streak against a blue petal.
Colors Irises Do Not Naturally Express
Despite the wide color palette, the iris genus cannot naturally express a few pure colors due to genetic limitations. The most notable absence is a true scarlet red. Irises can achieve deep reddish-brown, maroon, or burgundy shades, but they lack the specific genes needed to produce the pure red pigments found in flowers like poppies or roses.
This limitation exists because iris anthocyanins are primarily derived from delphinidin, which favors the blue and purple end of the spectrum. While many cultivars are marketed as “black” irises, they are not truly black. These flowers are actually extremely dark, saturated shades of purple, violet, or deep reddish-brown that appear black to the eye.