Antirrhinum majus, commonly known as the snapdragon, is a popular ornamental plant. Gardeners prize this flower for its signature bloom, which resembles a dragon’s face that appears to snap open when squeezed. The species has been extensively bred over centuries, resulting in a remarkable array of colors that add vertical interest and texture to flower beds.
The Wide Spectrum of Colors
The snapdragon offers one of the most comprehensive palettes in the flower world, covering nearly every shade imaginable outside of a true blue. Cultivars are available in fiery reds, warm oranges, and brilliant yellows, providing intense, saturated color for the garden. These warm tones range from soft peach and salmon shades to deep, almost fluorescent scarlet.
The cool end of the spectrum is represented by a variety of pinks and purples. Breeders have developed snapdragons in delicate rose, rich magenta, and vibrant lavender hues. White varieties are also common, ranging from pure, crisp white to creamy ivory, which serve to visually separate and highlight the more intense colors nearby.
The darkest colors available are typically deep maroon or burgundy, which can sometimes appear nearly black in certain light conditions. A true, genetically stable blue snapdragon remains an elusive goal for breeders, as the plant lacks the specific pigment chemistry required for that color.
Bicolor Patterns and Markings
Beyond solid colors, the snapdragon is highly valued for the intricate patterns and markings that appear on a single bloom. Many varieties display a bicolor effect, where the main petal color is dramatically contrasted by a different shade in the throat of the flower. For instance, a cultivar may feature deep red petals that transition to a striking yellow or white accent on the lower lip of the bloom.
These contrasting throats often serve as nectar guides, visual signals directing pollinating insects into the flower’s center. Other patterns include subtle speckles or distinct stripes that run vertically down the petal lobes. The existence of these defined patterns, such as the ‘Night and Day’ variety with its deep red and white contrast, highlights the complex genetic control over pigment deposition in the petals.
How Pigments Determine Color
The extensive color range of the snapdragon is determined by two main classes of chemical compounds known as pigments. The first class is the anthocyanins, which are water-soluble flavonoids stored in the cell vacuoles. These compounds are responsible for generating all the red, pink, purple, and maroon shades found in the flowers.
The specific shade of an anthocyanin-based color is influenced not just by the type of anthocyanin molecule present, but also by the pH level within the flower’s cells. A more acidic environment within the vacuole will push the color toward the red end of the spectrum, while a less acidic environment can shift the color toward the purple or lavender hues. These minute pH fluctuations create the subtle differences between a rose-pink and a magenta flower.
The second primary class of pigments is the carotenoids, which are fat-soluble compounds contained within specialized organelles in the flower cells. Carotenoids are responsible for producing the vibrant yellows and oranges seen in many snapdragon varieties. The presence or absence of these two main pigment classes, combined with genetic factors, dictates the final color and pattern of the bloom.