Natives of the Mediterranean, cornflowers (Centaurea cyanus) were originally introduced to North America as ornamentals. Upon escaping cultivation this pretty flower spread throughout most of the continent and now, in addition to being a favorite of gardeners, is often considered a noxious weed because it invades cultivated croplands. The common name, cornflower, comes from the United Kingdom where fields growing grains are called cornfields. Other colloquial names include bachelor’s buttons and bluebottle. Cornflowers can also be found along roadsides and other disturbed or waste areas.
Cornflowers, like other members of the sunflower family, have ray and disc flowers arranged in a head. The showy flowers at the ends of long stalks can be blue, purple, red, pink or white. The outer ray flowers are deeply lobed, funnel shaped and sterile. The fertile, inner disk flowers also have a funnel shape. High in nectar, butterflies and bees are attracted to cornflowers, which bloom in summer and autumn.
The strong, fibrous stem is grey-green and originates from a taproot. The simple or branched stems can grow up to three feet in height and are covered by soft, wooly hairs. The narrow, alternate leaves are usually entire on the upper plant but lower leaves can be toothed or lobed. The leaf undersides, especially lower on the stem, are cobwebby with fine intertwined hairs. Leaf stalks are short or absent. The fruit is a one-seeded elliptical achene, hairy at the base and fringed by a circle of stiff brownish bristles at the top.
Cornflower flowers are edible and often used to add color to salads. Fresh or dried the flower petals add flavor to tea and are often used to decorate dried tea blends. A decoction of flowers (flower water) is mildly astringent and antiseptic. Cornflower water is most often used to treat conjunctivitis or as a skin toner. Adding cornflower flowers to alum water produces a blue dye that is edible (food coloring) and can also be used to dye cloth, although the color in cloth is transient.
These cornflowers were growing in a vacant lot in Lookout CA (Modoc County).