Centaurea is a genus of around 700 different species, belonging to the sunflower family.
You’ll find the majority of these fantastic flowers come from the Eastern hemisphere, though they are grown across the world for their vivid color and beauty.
Centaurea cyanus is the one most people mean when they call a plant a cornflower, or bachelor’s button, and one of the most popular and well-known species within the genus.
Centaurea At A Glance
You can recognize these plants by their stems which are covered in silvery hair, their upright growth habit, thin leaves, and bright flower heads which are often made up of tiny, individual flowers.
Cornflowers may be annuals or perennials, and in the case of Centaurea cyanus, all are annual plants.
No matter what type you go for, they are sure to bring plenty of pollinators into your garden, which also boosts your garden’s overall health, and makes sure that most flowers get pollinated.
You’re probably most familiar with the blue cornflower, but they also come in other colors, including pink, red, burgundy, white, and purple.
While they are a staple of many gardens, including kitchen gardens, they are becoming increasingly threatened in the wild, not only due to the use of pesticides, but also intensive farming, and dedicating more land to farming practices.
It’s reported that when Tutankhamen’s tomb was discovered, there were cornflowers and mayweed, and despite how long they had been sitting there (for over 3000 years), they still had most of their color.
This is also said to indicate when he was buried, as both flowers would have been in bloom around March and April.
Cornflowers were particularly popular with the Victorians, and you’ll see them entrenched in many art forms, including illustrations, poetry, scrapbooking, and paintings.
It’s also a great companion plant, particularly for attracting insects which prey on moths such as the cabbage moth, helping to increase yields of cabbages and other crops, without using harmful insecticides.
The genus name comes from the Greek kentauros, meaning centaur.
In Greek myth, Chiron was the wisest and most just of all centaurs, and who had a vast knowledge of medicine and herbs, which he passed onto mankind, and used Centaurea flowers to heal.
The common name, cornflower, refers to the way that these flowers typically appear as weeds in fields used for growing crops such as wheat, rye, and oats.
Also known as the bachelor’s button, the cornflower was worn in a buttonhole to show a bachelor’s affection for someone.
It was said that if the person they loved didn’t return their feelings, the flower would wilt within a day.
Both names apply to all the flowers under the genus, though they also refer specifically to Centaurea cyanus, too.
Cornflowers represent love, devotion, passion, remembrance, hope, and peace.
For others, these flowers symbolize good luck, abundance, success, and looking toward the future.
Many flowers within the genus have roles in traditional medicine and herbal remedies.
They have a wide range of applications, including stomach problems, topical skin issues, infections, fever, and in a compress to soothe irritated eyes.
Centaurea cyanus is highly pigmented, and is a natural source of blue dye, or even blue ink if you prefer.
The flowers of most species within the genus are also safe to eat, and the taste is similar to cloves, with a sweet, spicy note.
Cornflower Growing Requirements
Cornflowers are hardy in USDA zones 2 through to 11, and depending on the species and when you plant them, they will bloom in spring or summer, sometimes stretching into fall, too.
Depending on the variety you go for, these plants can reach anywhere from 30 cm to 3 feet tall.
They will survive in dappled shade, but prefer full sunlight, where you’ll be able to enjoy as many of the flowers as possible.
Cornflowers love soil which has great drainage, and while they’ll flower best in nutrient-rich compost, they will also do well in sandy, or poor soil without many issues.
They are very easy to care for, even easier to raise from seed, and will provide your garden with plenty of color for very little effort.
If you’re looking for Centaurea flowers in summer, sow the seeds in the last few weeks of spring. You can also sow seeds in early fall if your climate is moderate enough, which means they will flower during early spring.
The only maintenance that you need to carry out is to take off dead flowers, which encourages the plant to produce more blooms.
Cornflowers are fairly robust, and don’t suffer from many diseases or pests. There are a few to watch out for, however, including stem diseases if they are planted too closely together, or powdery mildew.
They can also fall victim to aphids, in which case planting them near marigolds and alliums will help prevent large infestations.