The genus Lupinus, commonly known as lupine, encompasses a wide group of flowering plants recognized for their striking, upright flower spikes. These plants are found both as common wildflowers and as highly cultivated garden specimens, with centers of diversity across the Americas and the Mediterranean. The color of a lupine is highly variable, depending significantly on whether the plant is a native species or a modern hybrid developed for ornamental use.
The Defining Hues
The foundational colors of lupine, especially those native to North America, are predominantly saturated shades of blue and purple. Wild species like Lupinus polyphyllus, often called the Bigleaf Lupine, naturally display deep blue-violet flowers in dense clusters. This deep coloration historically defined the plant, giving rise to regional common names such as “bluebonnets” for several related species in the southwestern United States.
The anthocyanin pigments responsible for these deep hues are common in the parent species used to create the modern garden varieties. While some native species, such as the Tree Lupine (Lupinus arboreus), can be yellow or white, the classic color associated with lupine remains the dark spectrum of blue and purple.
A Palette of Cultivated Varieties
The introduction of hybridization dramatically expanded the lupine color range beyond its native blues and purples. The most famous example, the Russell Hybrids, developed in the early 20th century, transformed the plant into a garden staple by incorporating a vast spectrum of non-native colors. This breeding program produced varieties that exhibit brilliant yellows, fiery oranges, vibrant reds, and soft pinks, alongside pure creams and pristine whites. The careful selection and crossing of species like Lupinus polyphyllus allowed breeders to stabilize these new pigment combinations.
Many cultivated varieties also feature bi-colored or tri-colored flowers, where different petals on the same flower display contrasting shades. For instance, the upper petal, known as the standard, might be a pale yellow while the lower wing petals are a contrasting deep rose or purple. This engineered diversity means that colors available in nurseries—from apricot and coral to magenta and lemon yellow—are distinct results of cultivation, rarely occurring in the wild forms.
How Color Appears on the Plant
The overall visual effect of lupine color in a landscape is determined by the plant’s unique floral structure, not solely the individual petal pigment. Lupine flowers are small, pea-shaped blooms clustered tightly together on a tall, conical or pyramidal spike called an inflorescence. This dense arrangement causes the hundreds of individual colors to merge, creating a powerful, saturated color impression.
The height of the flower spike, which can reach over three feet in some varieties, contributes to the vertical display of color. The density of the flowers on the raceme influences how solid the color appears from a distance. A tightly packed spike delivers a uniform, intense block of color, while a looser arrangement allows more light and shadow to play across the individual blooms. The perceived hue also changes dramatically with light conditions; for example, a deep purple spike may appear nearly black in low light, but glows with a rich violet when illuminated by direct sunlight.