Cornflowers normally call up dreams of sky blue flowers waving at a summer breeze. Although both yearly cornflower (Centaurea cyanus) and perennial cornflower (Centaurea montana) typically athletic bright blue blooms, they also appear in a range of pink, lavender, violet, white or purple. Cornflowers range in height in tall 3-foot varieties to dwarf cultivars only 6 inches high. Whether you add them to a perennial garden, develop them for cut flowers or plant them at flowerbeds, cornflowers create a drought-resistant and deer-resistant inclusion your garden.
Yearly Cornflower
Yearly cornflowers (Centuarea cyanus), also referred to as bachelor’s buttons or blue bottle, are spring during summer bloomers. In addition to the conventional blue cornflower colour, you can find them in purple, purple, purple and white hues. The blossoms are 1 1/2 ins with ragged petals. Conventional yearly varieties grow 2 1/2 to 3 feet tall and spread 6 to 12 inches wide. They are able to topple over from the end as they reach their full height, requiring you to stake them. Plant yearly cornflowers in cutting gardens and cottage gardens or add them to meadow gardens for a wildflower look. Although considered an annual, these cornflowers tend to self-seed from year to year.
Dwarf Annual Cornflower
Smaller varieties of yearly cornflowers are acceptable for putting in flowerbeds and containers. “Dwarf Blue Midget” (Centaurea cyanus “Dwarf Blue Midget”) sports flowers of true blue color. It grows only 6 to 12 inches tall, blooming from June through September. “Florence Mix” (Centaurea cyanus “Florence”), another compact cornflower, tops out at 6 to 12 inches tall. In addition to blue flowers, “Florence Mix” contains shades of close white, pure pink and white. It blooms from June through August.
Perennial Cornflower
Perennial cornflower (Centaurea montana) is a showy, 2-foot broad and tall plant which blooms from May to June. It exhibits just one 2-inch fringed purple blue flowers with purple to red centers. Hardy at U.S. Department of Agriculture plant hardiness zones 3 through 8, perennial cornflower is also referred to as mountain bluet. Spreading by underground stolons, perennial cornflower rapidly forms colonies. Its bright blue flowers make it a great addition to the cutting or cottage garden.
Perennial Cornflowers With Unusual Colours
Added cultivars of perennial cornflower add interest to your garden with colored leaves or unusual flower colours. “Gold Bullion” (Centaurea montana “Gold Bullion”) exhibits golden-hued leaves and lavender flowers with maroon centers. It grows 1 to 2 feet tall and is hardy in USDA zones 3 through 8. Exotic looking “Black Sprite” (Centaurea montana “Back Sprite”) grows 30 to 35 inches tall. It’s dark purple to black star-shaped flowers and is hardy in USDA zones 3 through 9. To get a midsized perennial cornflower with heavy purple flowers, plant “Amethyst Dream” (Centaurea montana “Amethyst Dream”), that grows 18 to 20 inches tall. An early to midsummer bloomer, it is hardy in USDA zones 3 through 9.