The annual, herbaceous cornflower with its bright blue flower head is one of the typical symbols of summer. It adorns the garden from May until late autumn. Before the farmers drove them out of the grain fields, they swayed in the gentle summer wind together with poppies and chamomile. Their coloring is no longer limited to the bright blue. Eager breeders have succeeded in numerous other colors that give the hobby gardener even more pleasure in sowing and caring for these undemanding sun worshipers. With a growth height of between 20 cm and 100 cm, the cornflower is also a pleasantly variable garden design element.


Since sowing is so easy, only a few garden centers offer ready-made cornflower plants. Therefore, the hobby gardener starts sowing indoors from March.

  • Fill the seed tray or small pots with potting soil
  • Spread seeds and cover thinly with soil
  • Moisten with a spray bottle and place in a mini greenhouse
  • Alternatively, cover the culture vessel with cling film
  • Place in a bright, warm window seat that is not in full sun
  • Air the foil from time to time and keep the seed slightly moist

It is essential to only use special potting soil. Ideally, a little sand is added to this so that it is nice and permeable. Conventional potting soil is usually already pre-fertilized, which would not do well to the delicate cornflower seeds. If you want to be absolutely sure that the potting soil is really free of spores, viruses or insect eggs, place it in the oven at 200° for about 20 minutes before use and then let it cool down.

Idea: It doesn’t necessarily have to be professional growing containers in which the cornflowers are sown. A yoghurt pot with a small hole in the bottom to drain water, or cardboard tubes cut into pieces and placed in a bowl work just as well for sowing.
  • As soon as the first leaves appear in addition to the cotyledons, prick out
  • Carefully repot young cornflowers into their own small pots
  • The substrate still consists of the nutrient-poor seed soil
  • Now remove the foil completely
  • Keep seedlings slightly moist and protect from direct sun

By mid-May, the Centaurea cyanus will have rooted their seed pot well and are strong enough to be planted in a bed, bucket or window box.

direct sowing

Not every hobby gardener has enough space in their home to prefer the cornflowers. In this case, direct sowing is recommended from mid-April. This means that the seeds are sown where they will spend the summer.

  • Clean the bed soil from all weeds, roots and stones
  • Loosen up with a rake and smooth out with the rake
  • Apply seeds of the cornflowers in rows or by broadcasting
  • Then cover thinly with soil using the rake (light germinator)
  • Spray with a light spray of water so that nothing is washed away

It is advisable to then cover the seed with a bird protection net so that the seeds are not picked up immediately. Direct sowing in the protection of a cold frame is even more advantageous, so that late frosts on the ground cannot harm the young plants.

As soon as the seedlings have grown a few centimeters high and the bed becomes too narrow, the weaker specimens are sorted out. During this phase, the experienced hobby gardener weeds at least every 1 to 2 days so that the young cornflowers are not overgrown.

location and plants

Cornflowers prefer a sunny, sheltered spot in the garden. They also do well in a semi-shady location. They do not place high demands on the quality of the potting soil; The main thing is that it is well drained and there is no waterlogging there, because the summer flowers cannot cope with that at all.

From mid-May, cornflowers that have been grown indoors move into the bed, bucket or window box. The preparation work for the potting soil is the same as for direct sowing. In the planter, conventional compost-based potting soil is used as the substrate, to which 1 part sand is added.

  • While still in the pot, the cornflowers are placed in a vessel with water.
  • In the meantime, the gardener digs the planting hole.
  • The excavation is enriched with a little compost and horn meal.
  • The cornflower is potted and planted in the bed.
  • After the earth has been trampled down, the flower receives another dose of water.
  • The planting distance is between 30 cm and 45 cm, depending on the variety.

By the way, the cornflowers make a beautiful picture when they stand together in small tuffs with 3 to 5 plants. If it can’t be colorful enough for you, you can mix and match blue, pink, crimson, yellow and lilac varieties.

watering and fertilizing

In their Mediterranean homeland, cornflowers are not exactly spoiled with rainwater, so they do not need frequent watering in the home garden either. From time to time they gladly accept a ration of additional nutrients. However, the experts advise only starting to fertilize shortly before flowering, because otherwise the risk of over-fertilization is too great.

  • Water only during prolonged drought
  • Water regularly in the planter
  • If possible, do not splash over flowers and leaves
  • Cornflowers in the bed receive good garden compost every 14 days
  • In the flower box or bucket there is weekly diluted liquid fertilizer
Tip: If withered flowers are cleaned regularly, the cornflower will sprout more new flowers. In addition, the flowering period is significantly extended into October.

To cut

Cornflowers make excellent cut flowers for the vase. The higher-growing varieties in particular decorate the home with their bright colors, which form an enchanting contrast to the lush green leaves. The best time to cut the cornflowers is late morning, when the morning dew has evaporated. So that rot does not form in the flower water, the leaves are removed from the stalk in those places that stand in the water. If a small pinch of sugar is added to the flower water, this extends the residence time by several days. In addition, it is advisable to change the water every day, which also contributes to a longer flowering period and also prevents the unpleasant smell that stale flower water likes to spread.


The cut Centaurea cyanus are still among the most popular dried flowers, because you can use them to create graceful dried arrangements. If only the flower heads are dried, they enchant the set table into a banquet with rural charm.

  • Loosely tie the picked cornflowers together into small bouquets
  • Hang upside down in an airy, dry place
  • After 3 to 4 weeks they start to rustle as a signal that they have dried
  • If only the flowers are to be dried, the buds that have just opened are suitable

It is important to note that the cornflowers should not be exposed to the sun while they are drying, as they will either fade or the white flowers will turn yellow.

diseases and pests

The cornflower is often attacked by spider mites. If white webs appear on the underside of the leaves, this is an unmistakable signal of an infection. They appear in their thousands, especially on warm summer days, and it is mainly the voracious larvae that damage the flowers.

  • Insecticides based on rapeseed oil help in the early stages of infestation.
  • Pack the bucket airtight in foil for several days
  • PP predatory mites have proven to be an effective control agent.
  • Nematodes are also suitable for getting rid of spider mites.

In any case, it is advisable to take action against spider mites, even if until then it is ‘only’ the cornflowers that fall victim to them. The pests will spread through the entire garden at lightning speed and will not stop at valuable perennials.

If a too damp, dark location is chosen for the cornflower, it is susceptible to powdery mildew. In this case, white-grey spots first appear on the upper side of the leaf, which can later also be seen on the underside of the leaf.

  • Cut off all affected shoots and dispose of with household waste.
  • Spray the flowers repeatedly with tansy decoction or horsetail tea.
  • Neem oil-containing preparations from specialist shops also help to combat it.

Next year, under no circumstances should cornflowers be sowed or planted again in this area.

Beautiful varieties

Wilde Kornblume (Centaurea cyanus)

  • Growth height 40 cm to 80 cm
  •  purple-blue flowers from June to September

Silver knapweed (Centaurea bella)

  • Growth height 20 cm to 30 cm
  •  silver-grey foliage with pink flowers

Alpenkornblume (Centaurea montana)

  • Growth height 40 cm to 70 cm
  • cornflower blue flowers from May to July

Giant knapweed (Centaurea macrocephala)

  • Growth height 100 cm to 180 cm
  • yellow flowers from June to September/October

Kornblume ‚Rote Lola‘ (Centaurea cyanus ‚Rote Lola‘)

  • Growth height up to 80 cm
  • red, double flowers May to August/September

Kornblume ‚Black Beauty‘ (Centaurea cyanus ‚Black Beauty‘)

  • Growth height up to 80 cm
  • black double flowers from June to September

Weiße Kornblume (Centaurea cyanus ‚Snowman‘)

  • Growth height 70 cm to 100 cm
  • pure white flowers from June to September

This is just a small part of the fascinating variety of cornflower varieties that experienced breeders have been able to produce so far.


Once the cornflower has established itself in the garden, it reliably reseeds itself every year. Either the seeds overwinter in the ground, after which they germinate quite early in the following spring. On the other hand, there are also a few varieties that germinate in autumn and survive the winter as tiny seedlings and bloom in time for the beginning of spring. If you harvest the tiny seeds yourself in autumn, keep them in a dry, dark container in order to sow them next spring. However, this method does not guarantee varietal propagation because it is questionable which properties of the parent plants will prevail in the seeds.

Incidentally, in the course of the summer, propagation by division of cornflowers can be carried out without any problems. To do this, the mother plant is dug up, cut with a knife into several parts that have at least two buds, and then replanted in the new location. Finally, plenty of water is poured on and a little compost is administered.

However, other methods of propagation, such as cuttings or planters, are far too costly given how easy it is to sow in spring.

For many hobby gardeners, the cornflower is associated with fond childhood memories. After all, she was a faithful companion through the summer at the edge of the cornfields next to red poppies and white chamomile. How good that she is now returning to nature after a few years of absence. Therefore, it should also be given a regular place in the lovingly tended ornamental garden, no matter how small it may be. The brightly colored flower heads will definitely bring a good mood to the hobby gardener.

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