Why Do Violets Change Color?

Flower Pigments

• The color of a given flower is created by the compounds contained within the petals. Classic violets contain a mixture of red and blue anthocyanidins; these plant pigments reflect certain types of light, resulting in the perception of a pure violet color. The relative quantities of these pigments can be affected by any number of things. For example, over-watering the violets can dilute the pigment and, as a result, the petals may turn from violet to lavender.

Genetics

• When propagating violets it is not unusual for the offspring to produce flowers of a different style or color than the parent plant. This is the result of hybridization. When two plants are crossed, the result is a plant that displays traits common to both original plants; however, when the hybrid plant reproduces, the progeny may display the traits of the hybrid or of the plants that were used in its creation. For example, when a white violet is crossed with a dark purple one, the result is a plant with pale lavender flowers. When the lavender plant reproduces, the flowers from its offspring may be lavender, purple or white.

Soil pH

• The pH of the soil is a measure of its acidity; the lower the pH, the more acidic the soil. While some soils have a naturally low pH, most soils are neutral or only slightly acidic. However, common amendments such as mulch, compost, manure and coffee grounds tend to be acidic. Incorporating these compounds into the soil can result in a temporary shift in pH that can alter the shape of anthocyanidins, causing flower petals to change color.

Age

• As violets mature, their petals naturally fade. Like many flowers, the color of the violet is meant to draw pollinators. Once the pollination process is complete, the vivid blooms begin to lose their color. This is nature's way of telling potential pollinators not to waste their time as their presence is no longer necessary.