2001- The Year of Centaurea |
This year the National Garden Bureau celebrates the Year of Centaurea, and no matter what you call them--cornflowers, bachelor’s buttons, basket flower, or the old-fashioned blue-bottle--members of the genus Centaurea are wonderful additions to a garden. Even if they weren’t great cut flowers, which they are, the blue color of the species would make them desirable. They have been grown in American gardens since Colonial times, primarily from seeds brought over from Europe.
History- Most centaureas originated in Europe, where they still inhabit fields and waysides today, but a few are native to the Americas. They have been part of gardens for centuries, going back to ancient times. In fact, the genus name, Centaurea has its basis in Greek mythology. One of the centaurs, Chiron, is said to have used the flower to heal wounds, including his own, after battle. The most peaceful of the centaurs (who were a warlike group of half man-half horse), Chiron is credited in myth with teaching mankind about the healing powers of herbs.
There are many species of centaurea, but the most readily available as seeds or plants are Centaurea cyanus, cornflower, or bachelor’s-button; C. americana, basket flower; and C. montana, mountain bluet, or perennial cornflower. Cornflowers are appropriately named--they grow wild in corn fields in Europe and the United States and bloom basically until the harvest season begins. The blooms of basket-flower give it its name: Because of the ray-like outer petals, the heads look as if they are set in a shallow basket. The term bachelor’s-button refers to the long-lasting quality of the flower when it is cut and placed in the buttonhole of a suit or shirt; decades ago, bachelors sported the flower when they went courting. The origin of bluet in mountain bluet is from France.
Annual bachelor’s-buttons and basket-flowers begin to bloom in late spring and continue through summer. C. americana, an annual native to the south central and southeastern United States, is hardy to Zone 4. Centaurea can tolerate low temperatures of 41 degrees Fahrenheit.
Native to the mountains of Europe, mountain bluet flowers from late spring to early summer. It is hardy to Zone 3 and produces fringed, violet-blue flowers with deep purple centers. Also a member of the Centaurea genus is the well-known bedding plant dusty miller. A perennial, C. cineraria is grown for its grayish foliage, not its rather unattractive purple flowers. Even though it is perennial to Zone 4, it’s best to treat it as an annual; it doesn’t come through winter looking very good.
This year the National Garden Bureau celebrates the Year of Centaurea, also known as cornflowers, bachelor’s buttons, basket flower, or the old-fashioned blue-bottle. Members of the genus Centaurea are wonderful additions to a garden. All centaureas look good as part of an informal or wildflower garden. They are especially attractive interplanted with red poppies and snapdragons, or mixed with daylilies in a border. They also belong in cutting gardens in mixed color combinations or in blocks of individual colors. The foliage may become rather ragged and unbecoming as the season progresses—especially if the season has been rainy or very hot—so set plants in borders or beds where the leaves and flowers of other annuals and perennials will camouflage them.
Many bachelor’s-buttons branch naturally, but you can pinch the growing tips to encourage more branching, bushier growth, and more flowers. C. americana does need to be pinched, or you may end up with single-stalked plants. Pinching perennial cornflower will also give you more flowers, but it isn’t required. For slightly larger flowers, you can remove the buds from young plants, but part of the charm of cornflowers is their small, thistle like blooms.
- Fertilize the plants monthly with a balanced fertilizer or use a slow-release plant food at transplanting time.
- Water infrequently; centaureas are drought tolerant, and the stems actually get rather floppy if the soil is too moist.
- Remove spent flowers to keep the plants producing new blooms.
- Centaureas will self-seed, but not reliably and not for more than a year or two. It is best to start annuals with fresh seed every year.
Because centaureas are quite drought resistant, they do very well in containers, where the soil can dry out quickly. Plant them in window boxes or standard containers in combination with other annuals, such as geraniums, zinnias (Z. angustifolia in particular), lobelia, fan flower (Scaevola), and dusty miller. Dwarf varieties, such as the Florence series, are the most adaptable to window boxes.
- Make sure the container has drainage holes in the bottom or sides. Use a lightweight, soilless mix, not garden soil. Garden soil may contain weed seeds, and it is heavier than a soilless mix—something to consider if you want to move the containers around or if you are planting a window box on a sill or railing on a deck or balcony.
- If you want to avoid the chore of fertilizing the plants during the season, incorporate a controlled-release fertilizer in the mix before planting.
- Position cornflowers among the other plants in a random placement; their sometimes-lax stems will weave through the other flowers for a delightfully informal look. Set dwarf cornflowers toward the front edge of the container.
- To plant, unpot plants and place them in the mix at the same level they were growing originally. Water the planting well.
- Check the soil in the pots daily in very hot weather and water as needed to keep it barely evenly moist.
- Fertilize monthly with a water-soluble plant food, if you didn’t use a slow-release fertilizer at planting time.
This information is provided by the National Garden Bureau, http:\\www.ngb.org |
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