The Centaurea montana flower was introduced to Britain from mainland Europe’s woodlands and mountain meadows sometime in the 16th Century. Also known as the “perennial cornflower”, this spreading evergreen has been grown in English gardens for centuries and its popularity continues to this day. Follow our cornflower grow guide and get your own gorgeous blooms growing today!
The Genus of Centaurea
Why do we love bushy, thistle-like plant so much? Explore with me further to find out the cornflower’s many wonderful qualities and why, in my humble opinion, it’s an essential perennial for garden borders.
There are so many planting choices for a flower garden. In fact, there are many more flowers than you could ever think of, for every soil and site possible. One reason we love this unusual leggy perennial has to be its ability to adapt to any given conditions. Once planted and given time to settle in, it’s basically there forever.
As a recognized naturalizing flower, it belongs in country cottage gardens, and formal estate gardens alike. Wherever you plant these colourful, clump-forming cornflowers, they bring a wealth of structure and colour. Furthermore, and most importantly, they attract a wide array of garden wildlife.
The cornflower belongs to the European Centaurea family. This is a genus of annuals and perennials that are grown for their intriguing, thistle-like flower heads. The Centaurea montana, our dear friends and most popular cultivated species, have purple thistle-like flower heads. Each head encased is by a ring of the brightest blue, slender ray petals. Together, the flower heads look like a mass of colourful stars.
Cornflower foliage has the same thistle-like appearance. Its growth is vigorous, grey-green in colour, and has an almost furry appearance from the thousands of tiny silvery hairs. The leaves, however, are long and ovate, not serrated like a thistle, and have a noticeable white mid-rib. Being an evergreen plant, they remain this wonderful silvery-green colour all year round.
Other cornflower species have alternative flower colours. In fact, some are purple, blue, white or pink, but all have similar foliage. We shall delve into other interesting varieties a little later on.
Centaurea Species’ Growing Habit
These are plants of a bushy habit, with a rather untidy and leggy appearance. I tend to create structure for mine when they’re placed at the front of a border. They can be better when planted in between other perennials a little further back. Additionally, this gives the stems more structure, as plants on either side help to hold them together, curtailing their wanderlust tendencies.
By mid summer, I recommend cutting them back to secondary stems. This will encourage more and more flowers. At full maturity, a height of up to 70 cm can be expected from these rather wonderful and old-fashioned sun-lovers, with a spread of around 60 cm wide.
It’s late January, and I actually see a small selection of flower buds on my cornflowers as I write this article. This is proof of how hardy and resilient they are to English weather. They’re true warrior plants!
I have listed some of the best varieties that I have come across, but take a look for yourselves and see which you prefer.
Centaurea montana “Carnea”
As with all cornflowers, the “Carnea” has an extended flowering season. As such, it provides valuable garden colour after other perennials have finished blooming. The flower heads consist of a deep pink and purple thistle surrounded with an outer ring of soft pink ray petals.
These very intricate blooms appear in May and continue through to the end of July. With a height of 45 cm and a spread of 60cm, the “Carnea” is a perfect front-of-border plant. It performs best in any sunny, well-drained spot.
Centaurea montana “Gold Bullion”
The name refers to this Centaurea’s golden-green foliage. It provides a bright, contrasting backdrop to the perennial cornflowers’ purple and blue flower heads. It’s similar in height and habit to the previous, but with a mass of lighter, golden foliage. Performs best in any well-drained soil in a sunny spot.
Centaurea montana “Amethyst in the Snow”
This magnificent perennial cornflower was introduced in 2002. Additionally, it’s the first bicolour cultivar of the “C. montana” species to be introduced. Alongside the low-growing, grey-green foliage, the deep amethyst and snowy white flower heads create a truly remarkable display from early May to the end of June.
It’s smaller than other varieties at just 40 cm tall, and great as a border “front runner”. Performs best in well-drained soil in a sunny spot.
Centaurea montana “Jordy”
The “Jordy” is a new twist on a classic cottage garden perennial. Its form and foliage are similar to type, but the entire flowers are stunning deep purple-plum in hue. I think this will become a very popular variety due to richness of colour. In my opinion, this would look stunning planted in a white flower bed—a superb contrast for dramatic effect.
Perennial Cornflower’s Medicinal Properties
Back in the Ancient Greek times, it is said in Greek mythology that the Centaurea’s magnificent healing properties helped to cure Chiron the Centaur when Hercules shot him with a poisoned arrow.
After much research on the subject, it’s clear that our common perennial cornflower has extensive medicinal values. In folk medicine, it has long been used for gynecological conditions, digestive problems, and skin complaints.
It seems this little garden flower is a powerful anti-inflammatory and analgesic. In addition, it’s valued as an anti-ulcerogenic, anti-fungal, and anti-bacterial treatment.
Cornflower tea is known to reduce fever, water retention and chest congestion.
Whoever would have thought it?
Planting your Centaurea
When to Plant
Plant a pot-grown specimen at any time of the year. Ensure that your soil is well-drained, and add some extra organic matter, which will help provide essential nutrients.
Alternatively, when buying seeds, these need to be planted in the early spring time when the risk of frosts has passed. Ensure your seed are of good quality and from a reputable seller, to avoid any disappointments.
I always plant my seeds into seed trays filled with a very fine compost and start them off in the greenhouse. This ensures good seed-to-soil contact and adequate temperatures, both of which are required for successful germination. Once I have some nice strong seedlings, I plant these in my flower beds around 12 inches apart with a little homemade compost.
Where to Plant your Seedlings
We’ve already established that cornflowers are a pretty versatile plant species. They will grow in almost all soils, apart from those with a large clay base, as they become cloggy and waterlogged.
The best site is a moderately sheltered one, in full sun or partial shade.
Staking your Plants
I only give my cornflower plants structure when they’re at the front of a border. You can use small canes or metal hoops to keep your flowers in the bed, rather than spilling out onto the pathways. When planted further back in the border, other herbaceous plants and shrubs tend to do this job just fine.
Caring for your Cornflowers
Watering and Fertilizing
Cornflowers are easy to look after, and practically thrive on neglect. They are quite drought tolerant, once planted and settled, and hate to be in waterlogged soil. I would let the weather take care of the general watering, unless there is a long dry spell and your plant starts to look somewhat insipid.
I use a slow-release fertilizer for all of my plants, which I combine into the planting mix. Throughout the productive growing season, I choose a balanced liquid feed which I dilute and use once every three weeks throughout the Summer months.
Pruning and Cutting Back
You can extend your cornflowers’ flowering period by cutting the long stems back to secondary stems. Do this once the first flowering period of flowering has come and gone—usually by mid summer. This promotes more flowers and keeps your flowers from getting too untidy. When they’ve bloomed again, cut the stems back to the basal mound.
Propagating from your Cornflowers
Multiply your plants by dividing large perennials in either autumn or springtime, and re-planting them where you wish. When lifting your cornflower plants, it’s worth noting that even the smallest piece of stem left in your soil will eventually grow and regenerate.
Pests and Diseases
Pezibear / Pixabay
Both of these common problems are of minor concern when growing Cornflowers. There’s a chance of powdery mildew on the foliage when the weather is hot and humid, but this isn’t common.
Aphids—those problematic sap-suckers—can be a problem, but I just give them a dose of insecticidal soap spray and that seems to do the trick.
Good Border Companion Plants
I like the mixture of blues, purples and whites in a flower bed. To me, this just works so well and creates more of a visual impact. With this in mind, I’d suggest planting your Centaurea montana with Phlox douglasii “White Admiral”, the lace flower “Orlaya grandiflora”, Delphiniums (both royal blue and white varieties), and White Lupins. Also add some glaucous foliage plants, such as Artesmia, Lavender and Euphorbia.
Trust me, the effect is truly stunning.