Freesia flowers, native to South Africa, are known globally for their delicate shape and intensely sweet, citrus-like fragrance. Freesias exist in a remarkably wide spectrum of hues, meaning there is no single answer to what color they are. Hybridization has expanded the natural palette, resulting in colors ranging from the purest whites to deep purples. This broad availability makes freesias a favorite for florists and gardeners.
The Spectrum of Freesia Colors
The color range of cultivated freesias is extensive and can be grouped into several vivid categories. Foundational colors include clean, luminous whites, which often feature a creamy or ivory undertone, such as those found in the original species, Freesia alba. These light shades are highly prized for their classic appearance and strong scent.
The warm end of the spectrum is represented by brilliant yellows and oranges. These colors range from bright lemon-yellows to deeper shades of apricot and rich, fiery orange. Cultivars in this group often display a striking vibrancy.
The pink and red varieties offer a lush range of color intensity. Shades begin with soft, blush pinks and extend to vibrant magenta, deep rose, and rich crimson. These colors are achieved through the heavy accumulation of pigments, creating depth in the petals.
The Genetics Behind Blue and Purple Shades
The blue and purple hues are often the most sought-after in the freesia family, yet achieving a true, saturated blue is genetically complex. Freesias can produce the anthocyanin pigment delphinidin, which is the precursor for blue color.
The presence of delphinidin alone is not enough to create a true blue flower color; the final shade depends on the acidity of the cell sap within the petal, known as the vacuolar pH. A lower, more acidic pH pushes the pigment toward pink or red, while a higher, more alkaline pH is necessary to shift the color toward blue.
Existing purple and lavender freesias are the result of careful breeding and hybridization, often producing shades closer to violet or bluish-lavender. These colors are achieved when the vacuolar pH is raised, modifying the delphinidin pigment. Scientists continue to explore the genetic mechanisms that control this pH modification to breed a stable, pure-blue freesia.
Understanding Freesia Pigmentation
The variety of colors in freesia petals is primarily determined by two main classes of chemical compounds: carotenoids and anthocyanins. Carotenoids are fat-soluble pigments responsible for the warm colors, specifically yellows, oranges, and some red-orange shades.
Anthocyanins are water-soluble flavonoids that produce the red, pink, purple, and blue hues. These pigments accumulate in the cell sap and are responsible for all colors except yellow and white. White freesias lack the genetic capacity to produce significant amounts of either carotenoids or anthocyanins, resulting in an absence of color.
The final shade of a freesia flower is a complex interaction between the specific pigments produced, their concentration, and the precise pH level within the petal cells. Subtle changes in any of these factors result in the wide array of colors seen across the freesia genus.