Beautiful Bountiful Bachelor Button
Whether it is known as bachelor button, cornflower, blue bottle, or mountain bluet as an annual or as a perennial, the beautiful, bountiful garden flowers in the species Centaurea have a spot in every landscape. They make excellent cut flowers and are perfect for dried arrangements. The National Garden Bureau chose them as the 2001 flower of the year because of their versatility and attractiveness.
Old fashioned annual bachelor buttons (Centaurea cyanus) derived their name from their long-lasting quality when cut. Bachelors often would sport one in their lapel buttonhole when they went courting. The flowers have been grown in the United States since colonial times when the seeds were brought over from Europe, but have been cultivated for centuries before the establishment in the Americas. The name Centaurea is derived from mythology. It is said that one of the centaurs, Chiron, used the flowers to heal battle wounds, including his own.
Although they are available in a range of colors, including pink, white, and lavender, the bright blues are the most popular. The vivid color pairs well with poppies, snap dragons, marigolds, and mixed in with daylilies in a border. The two-inch feathery blooms sit atop gray-green lance shaped leaves on 1-3 feet tall plants. They easily grow from seeds planted after danger of frost. If they are pruned back after their summer show, they will rebloom in the fall. Full sun is the best spot for these beauties and they tolerant a wide range of soils. They look good in both formal and informal gardens, or mixed into vegetable gardens to attract a bevy of pollinators.
If something more permanent is desired, look no further than Montana bachelor button or perennial cornflower (Centaurea montana). This species was also brought over by immigrants and is now found wild in every state except Alaska as well at throughout Canada, most often growing in mountain meadows. It is a commonly cultivated and appreciated plant.
Both the flowers and leaves are slightly bigger in the perennial species. This plant reproduces both by seed and by underground rhizomes. It is winter hardy, but may need to be divided after a few years. Snipping off the individual blooms and then cutting off the entire stem at the base when the bloom period is over will help prevent self-seeding and slow the spread. They are prolific and will fill open spaces with ease.
Bachelor buttons are relatively free of diseases and pests. Aphids can occasionally be a problem, but can easily be dislodged with a strong stream of water. Fungal diseases like powdery mildew can pop up if plants are spaced too closely. Make sure there is good air flow between plants and thin if necessary. If a problem occurs, remove and destroy any infected plants.
There are a few species of Centaurea that are invasive and care should be taken to avoid them in the landscape. Knapweed (C. stoebe, C. stoebe ssp., micranthos, and C. maculosa) looks similar to cultivated Centaurea, but have invaded open grasslands, prairies, open forests, orchards, cultivated fields, and field edges. They outcompete desired vegetation, increase soil erosion and consume soil nutrients. Therefore, it is important when purchasing plants or seeds pay close attention to the scientific name of the plant and get only the desired plants.
Carol Shirk
Certified Master Gardener