The common lilac, Syringa vulgaris, is a highly fragrant, spring-blooming shrub with a long history in gardens. Its popularity stems from its intoxicating scent and the impressive array of colors it presents as one of the first heralds of spring. While the color “lilac” itself is a soft purple shade, the species and its many cultivars offer a broad spectrum of hues. This range extends beyond the familiar lavender, allowing gardeners to choose the perfect color for their spring landscape.
The Spectrum of Lilac Colors
Lilac breeders categorize the flower colors into four main groups, representing the most common shades seen in commerce. The traditional color is the light purple or mauve that gave the plant its name, often referred to as Violet or True Lilac. Varieties in this group range from pale lavender, such as ‘Maurice de Vilmorin’, to deeper, rich violet tones.
The next major category is White, which is sought after for its clean appearance and powerful fragrance. These cultivars, such as ‘Beauty of Moscow’ and ‘Angel White’, lack purple pigment, resulting in pure white or sometimes very pale blush-pink flowers. White lilacs often provide a striking contrast when planted alongside darker purple varieties.
A third group consists of Pink lilacs, which range from a soft blush to a more saturated, true pink tone. Cultivars like Syringa x prestoniae ‘Miss Canada’ exhibit a rosy-pink color, providing a softer alternative to the purple shades.
The fourth established color class is Magenta or Reddish-Purple, which includes the deepest, most saturated colors available. These shades, sometimes described as wine-red, are seen in cultivars like ‘Andenken an Ludwig Späth’ and ‘Charles Joly’, offering a dramatic, dark bloom.
Clarifying Uncommon and Misleading Colors
Beyond the primary four categories, two color descriptions, “Blue” and “Yellow,” are often used but require clarification. Sky-blue lilacs do not exist, as the plant’s pigment chemistry limits the color expression to the purple-to-red spectrum. What are labeled as “Blue” lilacs, such as ‘President Lincoln’, are intense, deep lavender or soft, wedgewood-blue shades that are visually the closest to blue.
The rarest color is Yellow, found almost exclusively in the cultivar Syringa vulgaris ‘Primrose’. This variety produces a pale, creamy-yellow or primrose shade that can appear nearly white in bright sunlight. The ‘Primrose’ cultivar originated as a spontaneous genetic mutation from a white-flowered lilac, making it a distinct but muted member of the lilac family.
The Science Behind Lilac Pigmentation
The wide range of colors in lilacs is determined by water-soluble pigments called anthocyanins, which are stored within the plant’s cell vacuoles. Anthocyanins are responsible for the red, purple, and blue colors found in many flowers and fruits. In lilacs, the specific ratio and concentration of two main types of anthocyanin derivatives—cyanidin and delphinidin—dictate the final flower color.
A higher concentration of cyanidin derivatives produces reddish-purple and pink shades, while delphinidin derivatives lean toward the blue and violet end of the spectrum. White flowers result from a genetic inability to produce any anthocyanins. Unlike some other flowering shrubs, the color of a lilac’s bloom is genetically fixed and is not affected by changes in soil pH.