The other day I was out for a walk in my neighborhood when I saw a pair of goldfinches flitting through a bed of blue cornflowers. Backlit by the summer sun, the male goldfinch was clad in his bright yellow courting dress and the cornflowers were an especially vivid shade of cerulean blue. The picture was perfect and made me want annual cornflowers in my own garden.
I already have a few perennial cornflowers—Centaurea montana–with their thistle-like buds, gray/green leaves and wispy petals in shades of blue or pale purple. They are pretty and their Latin name always inspires a whimsical vision of small centaurs, the half man/half horse of Greek mythology, romping around the garden. I don’t grow any of the annual “centaurs”, also known as Centaurea cyanus or, more commonly, bachelor’s button, basket flower or blue bottle.
This seems like a grievous omission, since annual cornflowers are ridiculously easy to grow. In Europe before the wide-scale use of herbicides, they traditionally shot up, unbidden between the rows of corn in the fields just like the red corn poppies made famous in the World War I era poem, “In Flanders Fields”. Cornflowers relish poor dry soil, except while they are getting established, and thrive on neglect. If you cut them for arrangements or for their traditional use as boutonnieres or “buttonholes”, the cut stems last a long time. The plants, for their part, rush to produce more flowers and keep doing so until they are felled by frost.
Standing about three or more feet tall, standard cornflowers bloom on wiry stems, with rather coarse, medium green leaves. Dwarf varieties, like ‘Jubilee Gem’, introduced in 1937 and still available today, top out at a more compact sixteen inches. Standard or dwarf, the plant’s glory is the blossoms, which make them look almost like small mums or double daisies. The resemblance is not accidental. All the Centaureas are members of the daisy or Compositae family. In annual cornflowers, blue is the most common, and in my opinion, the best color, but the blooms may also be shades of white, blue/purple, darkest purple/black or pink. Seed vendors sometimes sell mixes incorporating all these colors.
Cornflower seeds arrived from their native Europe with the colonists and have flourished in American gardens ever since. First century naturalist Pliny the Elder wrote glowingly of the striking blue flower color and Thomas Jefferson grew the plants at Monticello.
Cornflowers are naturals combined with other summer stalwarts like snapdragons, marigolds and zinnias. Their long vase life also makes them a great choice for cutting gardens or beds. Naturalistic plantings, planned wildflower meadows and cottage gardens also make excellent backdrops for the vivid blue blooms and dwarf varieties are right at home in window boxes, where watering lapses will be less harmful to them than to some other plants. Bees love them, as do butterflies.
According to the Invasive Plant Atlas of the United States, Centaurea cyanus may be invasive in some locations. It does not seem to have reached the destructive magnitude of rampaging monsters like Japanese honeysuckle or kudzu, but it pays to be aware if centuarea invasiveness is a problem in your area.
Needless to say, cornflower is very easy to grow from seed. In mild winter climates, it can be direct-sown outdoors in the fall for bloom the following spring. Gardeners in cold winter areas should plant the seeds in pots, following seed vendors’ directions, several weeks before the last frost date. Happy plants will most likely self-sow, limiting work for the gardener to grubbing out unwanted seedlings.
Sometimes annual cornflower cell packs are available from nurseries and garden centers, but it is really almost as easy to grow them from seed. Some vendors may still offer seed packets and if you can’t get them planted this fall, save them in the refrigerator for next spring.
Select Seeds is among the vendors still shipping seeds for a good selection of varieties. Find them at 180 Stickney Hill Road, Union, CT 06076, 1(800) 684-0395; www.selectseeds.com. Free catalog.