Meadow and mountain knapweed, Centaurea – care

The distinctive beauties from the daisy family like it sunny. In order to experience the garden flower in all its bloom, it should only be a bright place in the light penumbra. Locations that are too dark reduce growth and often only lead to minimal flowering. As demanding as the meadow and mountain knapweed is in terms of where it is planted, the more tolerant it is of the soil. There are no special requirements for the consistency and pH of the soil. The substrate should only be rich in nutrients, which is conducive to the health and growth of the Centaurea.

watering and fertilizing

Like almost all flowering ornamental plants, knapweeds do not tolerate waterlogging or prolonged drought. Water regularly and ensure that the substrate is always kept moderately and evenly moist, especially on hot summer days. If possible, use rainwater. You can avoid waterlogging by mixing pebbles under the soil outdoors. With potted plants, on the other hand, a layer of broken pottery or lava chippings on the bottom of the pot promotes the faster drainage of excess water.

The Centaurea is not a plant that needs to be continuously supplied with artificial nutrients. Compost or horn shavings are mixed under the substrate only in spring and autumn. This is enough for the knapweed to grow and form its flowers. You can enrich soil that is too poor with large amounts of humus and compost when planting. Plants cultivated in pots can be supplied with liquid or slow-release fertilizer.

propagation

Knapweed can be propagated successfully and without much effort in two different ways:

Root division: With vegetative propagation, neither special care nor cultivation containers are necessary. The plants can be moved immediately to the desired location. The time for root division is preferably in early spring or autumn when the knapweed is not in the full growth phase. Dig up the knapweed completely and dismember the plant with a sharp ax or spade. You can immediately replant all separated parts of the Centaurea in a suitable place.

Seeds: Immediately after flowering in autumn, you should collect the Centaurea seeds and leave them to dry in a cool and not too humid place. From March you can grow the plants on the warm window sill or in the conservatory, direct sowing takes place outdoors from the beginning of May.

planting

Meadow and mountain knapweeds are traditional and extremely popular flowering plants, which not only cut a fine figure in the garden. The daisy family also enchants with its simple charm on the balcony or terrace. The plants only come into their own in groups, so never plant the herbaceous plants, which resemble cornflowers, alone. The flowering period of the mountain knapweed is between May and August, while the meadow knapweed blooms from June to October. Combine both Centaurea species and enjoy the delicate and long-lasting blooms of cottage garden plants. The ornamental plants are available in different flower colors, in addition to a soft pink or white colour, knapweeds with crimson,

outdoor

When sowing directly outdoors, the seeds are only lightly covered with substrate and watered firmly. Be extremely gentle and use the watering can spout to prevent the soil from being washed away. Keep the soil moist, the seedlings will appear green within about 14 days. As soon as the young knapweeds have reached a size of about 15 centimetres, they must be separated. The ideal planting distance is between 30 and 40 centimetres. Please note that the herbaceous ornamental plants can rarely be planted strictly in “rank and file” and like to unfold by themselves. Give the knapweed this freedom and cultivate the plants in near-natural beds.

Plants propagated by root division can be replanted immediately in autumn or spring. Dig a sufficiently large planting hole and enrich the excavation with humus and pebbles. Insert the meadow or mountain knapweed up to the root collar and gently press the substrate firmly. Water regularly in the following days to make it easier for the plant to root and acclimate to the new location.

Cultivation in the vessel

For pot plants – or if you want to start growing before the warm spring – you need nutrient-poor soil and shallow growing containers. Here, too, press the seeds only slightly into the substrate and regularly moisten the soil with a water sprayer. From a size of 10 – 15 centimetres, you can transplant the knapweed into humus-rich soil. Plant a maximum of two Centaurea in a flower pot. Because the more space you give the perennial plants, the more lush the growth of the flowers will be.

hibernate

Planted outdoors or sown at the right time, the firmly rooted ornamental flowers easily survive the cold season. Apply a thick layer of compost or brushwood. This not only protects the roots from double-digit minus temperatures, but also the plants with important nutrients. Wrap the knapweed planter on the balcony or patio in burlap or a warming fleece. The herbaceous plants should also remain in their place in winter. If the ornamental plants are relocated to a cool room, they could suffer damage when new growth occurs next spring.

To cut

The high-growth and undemanding Centaurea with its magnificent flowers not only comes into its own in the ornamental bed or on the terrace. Knapweeds are also considered hardy and long-lasting cut flowers. Combine the flowers, for example, with carnations, roses and lady’s mantle. The pruning stimulates the meadow and mountain knapweeds to a new, increased formation of flowers.

Before the Centaurea begins to sprout in spring, it is helpful for a healthy appearance if you prune the plant radically. In autumn, the withered shoots and leaves should not be removed under any circumstances. The cell juices of the knapweed migrate into the root interior, premature removal of the plant parts above ground could weaken the formation of new shoots in the following year.

diseases and pests

Discoloration and a conspicuous, stunted growth are not always necessarily due to an infestation of harmful insects or fungal pathogens. The cause often lies in care errors, such as excessive fertilization, incorrect watering behavior or the location is too dark. Prevent these factors and strengthen the health and resilience of meadow and mountain knapweeds.

Wrong mildew

Damp weather promotes infestation with this plant disease. The fungal pathogen penetrates the inside of the knapweed and constantly secretes toxic substances. You can recognize an infestation by a grey-violet coating on the underside of the leaves and light spots on the upper side. Not only can you successfully combat downy mildew , you can also prevent infestation with this fungal disease.

• Keep the distance between the plants.
• Never water over the leaves.
• Check regularly.

Remove affected shoots and leaves immediately. If the fungal pathogen has already infested more than half of the entire Centaurea, you should also dispose of them in the compost. It is impossible for downy mildew to spread via dead plant material. If you cannot contain the disease with conventional methods, you should resort to special fungicides. However, use them strictly as directed and avoid contact with edible crops.

spider mites

These pests, which are only a few millimeters in size, have also developed a taste for meadow and mountain knapweed. The cell sap of the plant serves as food for the arachnids. As a result, the leaves first have a silvery sheen before yellow discoloration appears on the surface and the leaves dry up. Other harmful insects also cause these symptoms, but spider mites leave webs on the shoots and the lower parts of the plant. You can quickly make these visible with a water sprayer. You should fight an infestation immediately to prevent it from spreading and to avoid the loss of the affected Centaurea.

Spider mites are sensitive to high humidity. If you have the opportunity, you should wet the affected plant sufficiently with water and then wrap it completely in foil. Maintain this state for a few days and repeat if necessary. But washing and spraying with soapy water or a stinging nettle decoction has also proven itself in the event of a mite infestation. At the same time, release natural predators such as ladybugs and spiders in the immediate vicinity of the affected plants.

root rot

A musty smell, which comes straight from the substrate, and a visibly ailing plant indicate root rot. This occurs with heavy soil and an excessive supply of water. If the roots of the knapweed have already been damaged too much and rot, the entire plant must be disposed of. Prevent this disease by loosening the soil with pebbles when planting.

Conclusion
Meadow and mountain knapweeds are undemanding summer flowers, which, however, only come into their own in a group with their full blooms. The daisy family gives your garden a wild and romantic atmosphere and at the same time serves as a rich source of food for bees and other useful insects.