No true blue peony is currently available in the commercial horticultural world. Peonies are popular garden flowers known for their large, lush blooms, naturally occurring in white, pink, red, coral, and yellow. Colors that approach blue, such as deep purples or lavenders, are often mistaken for the elusive shade. This perception frequently depends on lighting conditions and the specific cultivar viewed.
The Genetic Barrier: Why True Blue Eludes Peonies
The absence of a true blue color in Paeonia species is rooted in the plant’s genetics and biochemistry. Flower coloration is determined by pigments called anthocyanins, which are water-soluble compounds stored in the plant cell vacuoles. The spectrum of colors a flower can display is dictated by the specific type of anthocyanin present and the pH level of the cell sap.
True blue coloration requires the pigment delphinidin, responsible for blue hues in flowers like delphiniums and hydrangeas. Peonies lack the necessary enzyme, Flavonoid 3′,5′-hydroxylase, required to synthesize delphinidin. Without this genetic capability, peonies are limited to producing other anthocyanins, resulting in familiar red, pink, and purple shades.
Peony colors are based on cyanidin and paeonidin, which produce red and magenta tones. Deepest purples occur when pigment concentration is high and the cell environment is slightly alkaline, pushing the color toward the violet end of the spectrum. This biological limitation prevents traditional cross-breeding from producing a pure, sapphire-blue peony.
The Closest Alternatives: Cultivars Approaching Blue
Since a true blue peony is biologically impossible with current genetics, breeders focus on cultivars displaying cool-toned shades of purple, violet, and lavender. These varieties are the closest alternatives and are often marketed using “blue” in their descriptions.
Notable near-blue varieties include the Itoh peony ‘Cora Louise,’ an intersectional hybrid with large, semi-double blooms in a delicate lavender-white blend. The soft, light lavender shade can appear bluish, especially against the dark green foliage. Another example is the Itoh peony ‘First Arrival,’ which offers semi-double flowers in a vibrant lavender-pink hue that shifts depending on light quality.
For deeper, more saturated color, tree peonies like ‘Kamata-nishiki’ display dark purple, almost indigo-colored semi-double blossoms. The herbaceous peony ‘Nightlife’ produces double flowers in a deep, dark purple that is perceived as an intense violet. The perception of blue in these flowers is often enhanced by cool, overcast weather or soft morning light, which draws out the cooler undertones.
Manufactured Blue: Dyeing and Digital Deception
When a truly blue peony appears, it is almost always the result of artificial intervention. The most common method involves treating cut peony flowers with a blue floral dye. Florists place the stems of white or light-colored peonies in water mixed with a concentrated dye. The dye is absorbed through the stem’s vascular system, traveling into the petals. This creates a striking, sometimes streaky, blue color that is artificial and only achievable in a cut flower arrangement for events.
Beyond physical alteration, the appearance of a “blue peony” in media is frequently a result of digital manipulation. Photographers and advertisers use software to adjust the color balance of images. They exaggerate subtle lavender or violet tones until the flowers appear true blue. Filters and saturation adjustments can easily transform a deep purple cultivar into a vividly colored, yet botanically false, blue flower for online viewing.