Cornflowers Will Also Beautify Your Garden

In short: Cornflowers (Centaurea) are undemanding annuals and perennials that need a sunny spot and nutrient-rich, well-draining soil with enough calcium. Sow them directly in rows 25–30 cm apart in March to April, once temperatures reach about 10 °C. Remove spent blooms promptly so the plant is not exhausted.

Cornflowers (lat. Centaurea) belong to the Asteraceae family (lat. Asteraceae) of plants. The term cornflower probably brings to mind blue flowers bordering grain fields alongside poppies. However, in your garden you can grow, in addition to the classic blue cornflowers (lat. Centaurea cyanus), also purple, pink or white flowering specimens.

Cornflower Species

Very interesting in terms of flowers is the sweet sultan (lat. Centaurea imperialis). Its flowers are robust, full, and can have various colors – white, yellow, purple. Sweet sultan can grow up to 80 cm in height. The stems grow quickly, are upright and heavily branched. The leaves have a lanceolate, narrow shape, their color is grey-green. A multicolored group of these cornflowers will stand out in any flowerbed. Sweet sultan is suitable for cutting, lasting up to 10 days in a vase. Since this is an annual plant, yearly sowing is necessary, preferably directly in the flowerbed. Pre-grown plants tend to lodge.

A somewhat different type of cornflower is the giant knapweed (lat. Centaurea macrocephala), which blooms with large yellow flowers and, unlike classic cornflowers, is a perennial. Even complete beginners can successfully grow it because it is completely undemanding. It thrives in direct sunlight in drier, well-drained clay-sandy garden soils. Under ideal conditions it can grow to a height of approximately 120 cm. Giant knapweed flowers already in the first year of cultivation. There is also blue cornflower, meadow cornflower, field cornflower and garden cornflower.

Another perennial cornflower is the mountain cornflower (lat. Centaurea montana), which grows wild in foothill and mountain areas on meadows and at forest edges. However, it is also sometimes grown as an ornamental in gardens. Mountain cornflower grows to a height of 30 – 60 cm. The leaves are oblong, cobwebby-hairy on the underside. The outer ray florets are blue in color, the inner ones are purple. Mountain cornflower blooms from May to September. If you cut the plant back immediately after flowering, it will bloom again soon. Mountain cornflower and its two subspecies are protected by law, so do not destroy them in nature and grow them exclusively from purchased seeds.

Growing Cornflowers

Cornflowers are very undemanding to grow, so even complete beginners can plant them in their garden. Some cornflowers are perennials, others are annuals, but their cultivation is essentially the same. Perennial species last for many years, while annuals need to be resown each year. Cornflowers require a sunny location, though they can tolerate partial shade. The soil should be nutrient-rich, well-draining with sufficient calcium content. After hot summer days, cornflowers appreciate a few drops of water. Regular fertilizing isn't necessary, but if you occasionally add some fertilizer to the watering, it won't harm the plants. Cornflowers often become decorative elements in vases, and some species are also suitable for drying. Cornflowers should be dried in a dark, well-ventilated space. Cornflower blooms that weren't picked for vases or drying should be removed as soon as possible after flowering to avoid unnecessarily exhausting the plant.

Cornflowers are sown directly in rows spaced approximately 25-30 cm apart. Sowing is done in March to April when temperatures reach around 10°C. Greater knapweed can be pre-cultivated. Seed sowing is then carried out in March and April in seed trays, and actual planting in the bed is possible around May to July. The ideal spacing for planting greater knapweed is approximately 50 x 50 cm.

Uses of Common Cornflower

Dried common cornflower petals are used to make decoctions, from which compresses for tired eyes are prepared. They can also be used for conjunctivitis. Cornflower decoction has disinfectant properties and acts as a strong diuretic.

Interesting fact: Blue pigment from common cornflower petals was once a basic component of ink.