CENTAUREA CYANUS

Bachelor’s button, or Centaurea cyanus, is a European wildflower of the aster family that has naturalized across the United States.

It’s a vigorous grower that was commonly found growing among the grain crops of farmers.

Currently on the USDA’s list of Introduced, Invasive, and Noxious Plants, C. cyanus is prohibited in North Carolina.

Also known as cornflower, or garden cornflower, its delicate blossoms have been charming country folks for generations.

Robust and True Blue

One of several Centaurea cornflower varieties, but the only one commonly referred to as cornflower, C. cyanus is noted for its predominantly blue flowers that are typically found en masse in fields, and in the dusty gravel along roadways.

An annual that self-sows on viable ground, it gives the impression of being a perennial, returning each summer in all its glory, reaching heights of up to three feet.

Sturdy grayish-green stalks and leaves support delicate, multi-petaled disks that range in color from blue and purple to pink and white.

In my area, there is a sunny meadow full of cornflowers. Occasionally, the owner mows his property, and I’m always fascinated to see the flowers make a defiant, if stunted, comeback, blooming at ground level with almost no supporting stems.

This is a robust plant that’s so easy to grow, it’s recommended widely for gardening with children.

With full sun and well-drained soil, you should have blossoms all summer long.

Culinary Use

Bachelor’s button is also an edible flower that makes a tasty and attractive fresh garnish for cold salads. You can .

The sweet and spicy flavor of its flowers falls somewhere between cloves and black pepper, with field green undertones. (Or a taste that’s a little cinnamon-y, according to our reader David Hinkle Bettin via Facebook!)

If you plan to eat it, be sure to source the flowers from a reputable purveyor, or cultivate your own. Forage only if you are 100% certain you can identify this plant, and avoid areas where pesticides or pollution may be present.

Wash all flowers thoroughly before consuming.

To use flowers whole, simply snip off stems and place decoratively on or around cold foods just prior to serving.

To dress up a salad, snip off stems, separate flowerheads into individual blossoms, and sprinkle on top.

A Word of Caution

Flower consumption is not endorsed by the FDA, and may cause adverse digestive or allergic reactions. Use sparingly and with caution.

Centaurea cyanus Plant Facts

  • Average moisture
  • Average to poor, well-drained soil
  • Considered invasive in some areas
  • Prohibited in North Carolina
  • Easy to grow
  • Full sun
  • Grow from seeds or purchased plants
  • May reach 3 feet in height
  • Naturalized wildflower
  • Self-sowing annual
  • Tolerates drought
  • Zones 2 to 11

Where to Buy

Bachelor’s button seeds are available from True Leaf Market.

Bachelor’s Buttons – Mixed Colors

Mixed color packages are available in 3 grams, 1 ounce, 4 ounces, or 16 ounces of seed.

Room to Roam

Does your landscape have an expansive location, where the sun is strong, the grass doesn’t want to grow, and the soil is on the dry side?

This might be the ideal spot for a vigorous wildflower.

The easiest way to get started is to sow seeds. Given free rein, they can turn a barren swath into a ribbon of country blue you’ll never tire of admiring.

If you like to cut flowers for bouquets, let the plants grow tall. Alternatively, mow them to a height of four inches for a neater appearance.

Bachelor’s button is a low-maintenance plant. Once established, it takes care of itself, making it a good choice for xeriscaping. However, before you plant, be sure to check with your state’s extension service to determine if C. cyanus is prohibited in your area.

Are you familiar with bachelor’s button? Do you consider it invasive or inviting? Let us know in the comments section below.

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Product photo via Thrive Market. Uncredited photos: .

About Nan Schiller

Nan Schiller is a writer with deep roots in the soil of southeastern Pennsylvania. Her background includes landscape and floral design, a BS in business from Villanova University, and a Certificate of Merit in floral design from Longwood Gardens. An advocate of organic gardening with native plants, she’s always got dirt under her nails and freckles on her nose. With wit and hopefully some wisdom, she shares what she’s learned and is always ready to dig into a new project!

Cornflowers (Centaurea spp.) are small, free-flowering annuals with delightful sky blue flowers. They are easy to grow by seed and make a long-lasting cut flower, even retaining their color when dried.

Cornflower Facts

Cornflower seed is widely available in garden centers and seed catalogs, where it is also commonly referred to as bachelor buttons and occasionally by other names, such as basket flower of bluebottle. They are annuals for the summer flower garden, growing from one to three feet tall, depending on the variety. As an annual, they are suitable for all USDA zones.

Description

The foliage is spindly and nondescript, composed of inch-long lance-shaped leaves. They are grown primarily for their flowers – one to two-inch round clusters comprised of numerous tiny flowers – which bloom from early summer until the first frost.

Growing Information

Coneflower seed can be sown directly in the garden as soon as the ground can be worked in spring. They are not picky about soil, but benefit from a bit of compost being worked into the planting area. Plant the seeds about a half-inch deep and six inches apart in a sunny or partly sunny location. After they sprout, thin the weaker seedlings, leaving the rest spaced about 12 inches apart.

Cornflower seed can also be incorporated into wildflower mixes and broadcast over large areas.

In the Landscape

Cornflowers are typically combined with other annual flowers or mixed in with larger perennial species as an attractive filler. Plant them in wildflower meadows, cottage gardens, and perennial borders. They are one of the best species to include in beds for cut flowers.

Care

Cornflowers are very low maintenance plants though they do need regular irrigation throughout the summer to thrive. Removing the flowers as they fade will help to encourage repeat blooming. If you allow some seedheads to dry on the plants at the end of the growing season, they will likely sew themselves and return to the garden next year. By late fall, the spent stalks can be pulled out or cut to the ground.

Pests and Disease

Pests and disease are of minor concern with cornflowers. Aphids may show up, but are rarely too troublesome and can be dispatched with a sharp jet of water or an insecticidal soap spray. Powdery mildew can occur in hot humid places and is best dealt with by destroying any plants that become badly infected to prevent it from spreading.

For Medicinal Purposes

Cornflower is occasionally used for medicinal purposes, especially the flowers, which are used as an eyewash. If growing cornflower for this purpose, use the common species (Centaurea cyanus), rather than one of the hybrid cultivars, and harvest the flowers in the morning just after they open.

Varieties

A mix of cornflower varieties

Cornflower has been developed into a number of named cultivars and hybrids that offer different colors besides the traditional blue form. Mixing different colors in a single planting makes the colors more impactful.

  • ‘Burgundy Beauties’ has a mixture of deep purple and whitish flowers on plants about three feet tall.
  • ‘Dwarf Blue Midget’ is a blue flowered form that reaches only 12 inches tall.
  • ‘Florence Mix’ is also just 12 inches tall and has a mix of white and pink blossoms.
  • ‘Almost Black’ has deep purple-burgundy blossom on plants to three feet tall.

Simple Pleasures

Cornflowers are not large and spectacular, but they are brightly colored and cheery-looking. They are priceless as cut flowers and for inclusion in naturalized meadow plantings.

Browse

Corn Flower

Kingdom Plantae Order Asterales Family Asteraceae Tribe Cynareae Genus Centaurea

A drought tolerant annual, native to Europe, which has naturalized throughout North America. The upper half of the plant is multi-stemmed, producing many flowers. Leaves are covered with small white hairs causing the plant to have a blue-gray appearance. The original flower color is blue, but it is now available in white, pink and red. Prefers full sun in various soil types. An outstanding performer whether your preference is for cutting or admiring.

The blue cornflower has been the national flower of Estonia since 1968 and is a symbol of daily read to the nationals of the country. It is also the symbol of the Estonian political party, People’s Union, theFinnish political party, National Coalition Party, and the Swedish political party, Liberal People’s Party, and has also been a symbol of social liberalism in Switzerland since the 20th century. It is also the official flower of the Swedish province of Östergötland.

The blue cornflower is also considered one of the national flowers of Germany. Legend has it that when Queen Louise of Prussia was escaping Berlin and being chased by Napolean’s soldiers, she chose to hdide her children in a field full of cornflowers. She would keep them quiet by making garlands of corn flowers for them. The flower has since been synonymous with Prussia, and hence with ermany, when the two countries got unified in 1871.

How to grow a Corn Flower

  • Prep the soil and loosen it with a rake. Start working on it as early as in spring.
  • Scatter the seeds across the soil.
  • Cover lightly with a thin layer of dirt and pat gently.
  • Sprinkle the seeds with water and keep moist.
  • Plant the seedlings to 8 to 12 inches apart.
  • If sowing in winter, do so without worry, as they can endure the harsh cold and are very hardy.
  • Prepare a clear plastic container by poking holes in the bottom and in the lid.
  • Put one to three inches of dirt in the base of the container and thoroughly wet the soil.
  • Sprinkle the seeds on the soil.
  • Put into the soil.
  • Water the seeds.
  • Place the lid securely on the container and place outside.
  • Water the container as soon as the soil starts drying out.
  • As soon as the first true leaves arrive, transplanting can begin.

Corn Flower plant care

  • Place the plant such that it gets sufficient sunlight, but not too much of it. It can be put on a window sill too, as long as some kind of light covering can be arranged for. An indication of the plant getting excessive sunlight will be the leaves of the plant turning light green. Avoid placing the plant in an area where it might be in direct attack from a breeze or draft.
  • Before putting the plant in a container, fill the container with water and let it stay for 48 hours, so that the chlorine evaporates. When the top half of the soil is dry, you can beg9in watering the plant. Pour water close to the stalk, as its roots are close to that area and are very short.
  • Water should be added to this plant only when the plant is dry. To test dryness, insert a water gauge 2 inches below the top soil. Water the plant only if the gauge reads “dry” and keep watering until it reads “moist”.
  • Every alternate month, fertilize the plant with a liquid fertilizer while watering it.
  • As mentioned earlier, the roots of this plant are small. Therefore the plant should e kept in a small pot. Once it grows, a bigger pot can be opted for.
  • The height of the corn flower plant can be controlled by pulling out the center of new growth on the plant.

Learn About Cornflowers

Common Disease Problems

Aster Yellows: Plants are stunted, develop witch’s brooms (excessive growth), petals turn green and become deformed. This virus-like condition is spread by leafhoppers. Burpee Recommends: Remove infected plants and control leafhoppers. Remove weeds in the area which serve as alternate hosts to the disease.

Damping Off: This is one of the most common problems when starting plants from seed. The seedling emerges and appears healthy; then it suddenly wilts and dies for no obvious reason. Damping off is caused by a fungus that is active when there is abundant moisture and soils and air temperatures are above 68 degrees F. Typically, this indicates that the soil is too wet or contains high amounts of nitrogen fertilizer. Burpee Recommends: Keep seedlings moist but do not overwater; avoid over-fertilizing your seedlings; thin out seedlings to avoid overcrowding; make sure the plants are getting good air circulation; if you plant in containers, thoroughly wash them in soapy water and rinse in a ten per cent bleach solution after use.

Downy Mildew: This fungus causes whitish gray patches on the undersides and eventually both sides of the leaves. Burpee Recommends: Rotate crops. Avoid overhead watering. Provide adequate air circulation, do not overcrowd plants. Do not work around plants when they are wet.

Powdery Mildew: This fungus disease occurs on the top of the leaves in humid weather conditions. The leaves appear to have a whitish or greyish surface and may curl. Burpee Recommends: Avoid powdery mildew by providing good air circulation for the plants by good spacing and pruning. Contact your Cooperative Extension Service for fungicide recommendations.

Rust: A number of fungus diseases that causes rust colored spots on foliage and stalks. Burpee Recommends: Practice crop rotation. Remove infected plants. Contact your Cooperative Extension Service for fungicide recommendations.

Common Pest and Cultural Problems

Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Aphids are only a problem if the plants are stressed. Alyssum is used as a trap crop for lettuce. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps who feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.

Cutworms: These insects cut off the seedlings at the soil level. Burpee Recommends: Place a paper cup collar (use a coffee cup with the bottom cut out) around the base of the plant. They are usually mostly a problem with young seedlings. You can also control by handpicking and controlling weeds, where they lay their eggs.

Leafhoppers: Leafhoppers cause injury to leaves and stunt growth. They also spread disease. Burpee Recommends: Remove plant debris. Use insecticidal soaps. Consult your Cooperative Extension Service for other insecticide recommendations.

Spider Mites: These tiny spider-like pests are about the size of a grain of pepper. They may be red, black, brown or yellow. They suck on the plant juices removing chlorophyll and injecting toxins which cause white dots on the foliage. There is often webbing visible on the plant. They cause the foliage to turn yellow and become dry and stippled. They multiply quickly and thrive in dry conditions. Burpee Recommends: Spider mites may be controlled with a forceful spray every other day. Try hot pepper wax or insecticidal soap. Check with your Cooperative Extension Service for miticide recommendations.

Stalk Borer: The larvae of this insect tunnel up and down inside the plant stem causing the plants to wilt. By the time the plant wilts it is too late to save it. The larva is 1.5 inches long, greyish brown with one dorsal stripe and two lateral stripes on each side. The lateral stripes on the front half are interrupted and the lower brown stripe extends forward onto the side of the head. The eggs hatch in May to early June, after the moth lays them the previous September or October. Burpee Recommends: Remove and destroy all plant debris and nearby weeds.

How To Grow Cornflowers From Seed.

‘Blue Boy’ Cornflowers.

I would never be without cornflowers in the Higgledy Garden. Not only are they drop dead gorgeous and immensely productive but they are also very simple to grow and look after.

Cornflowers ‘Black Ball’

Cornflowers are what we can call, ‘cut and come again’ flowers…if you cut them above a leaf node then the little star will produce more flowers for you…albeit on slightly shorter stems. It’s a good plan to have a good proportion of your cut flower patch made up of ‘cut and come again flowers’….this way you will have flowers from May until the frosts, even from the smallest patch.

‘Boy Boy’ are great with any orange flowers you can get your mitts on.

How To Grow Cornflowers From Seed.

*First of all you need to find a space for them in free draining soil in full sun.

*The soil doesn’t need to be rich, in fact Blue boy cornflowers are rather delighted to be in the presence of poor soil. (Treat em mean keep em keen.)

*Rake the soil down to a fine tilth. By this I mean rake it down to small pieces no bigger than a marble.

*I make an September sowing and then a spring sowing…not sowing outside until mid April when the soil has warmed up.

*I tend to sow the seeds into three rows about a foot apart. This way when the plants grow it is easy to reach the middle from either side.

*sow the seeds thinly. A pack of Higgledy Garden seeds should be enough to cover twenty meters of a single row without any bother. Don’t do as I did on my first attempt many moons ago to use a whole packet of seeds in about three feet. Silly man.

*Prewater your seed drills…this stops the seeds from being washed away by watering afterwards.

*In three weeks you will see the little munchkins wiggling their way up out of the ground…thin them to about a foot apart. If you are careful you can move the seedlings if you don’t disturb the roots too much.

*Keep the bed weed free.

*Don’t let the ground dry out too much whilst they are growing.

*I put some pea netting up at a height of about two foot and let the plants grow through it. That way they get support, high winds can flatten a bed in no time….as I have discovered….grrrrrrrr

Ben

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