Practical
Plants

Centaurea nigra

Black Knapweed

a perennial member of the Centaurea genus in the family Compositae.

No photo available

Taxonomy and growth

Life cycle
perennial
Height
0.6 m
Fertility
Self fertile, Bees, Flies, Lepidoptera, Self
Flower type
hermaphrodite
Pollinators
Bees, Flies, Lepidoptera, Self

Uses

Edible uses

This section contains historical Plants For A Future notes marked noncommercial.

Flower petals - raw. Added to salads[3].

Plant part
Flowers

Medicinal uses

Historical medicinal uses. These records describe reported uses. They do not establish safety or effectiveness. Ask a qualified health professional before using any plant medicinally.

This section contains historical Plants For A Future notes marked noncommercial.

The roots and seeds are diaphoretic, diuretic, tonic and vulnerary[6][7]. The plant once had a very high reputation as a healer of wounds[6].

Product or use
Diaphoretic
Product or use
Diuretic
Product or use
Tonic

Environment

Range
Western Europe, including Britain, from Spain to Norway, east to Germany and Switzerland.
Habitat
Grassland, waysides, cliffs etc to 600 metres[2].
Light
full sun
Shade tolerance
no shade
Water
moderate
Hardiness
Zone 5+
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline, very alkaline
Drainage
well drained
Tolerances
drought
Tolerates Nutritionally Poor Soil
No
Drought
tolerant

Propagation

This section contains historical Plants For A Future notes marked noncommercial.

Seed - sow April in a cold frame. When they are large enough to handle, prick the seedlings out into individual pots and plant them out into their permanent positions in the summer. Division in autumn. Very easy, larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the summer or following spring. This should be done at least once every three years in order to maintain the vigour of the plant. Basal cuttings in spring. Harvest the shoots when they are about 10 - 15cm long with plenty of underground stem. Pot them up into individual pots and keep them in light shade in a cold frame or greenhouse until they are rooting well. Plant them out in the summer.

Cultivation

This section contains historical Plants For A Future notes marked noncommercial.

Succeeds in ordinary garden soil[1][4]. Prefers a well-drained fertile soil and a sunny position[4]. Tolerates dry, low fertility and alkaline soils[4]. Established plants are tolerant of considerable neglect, thriving and even self-sowing in dense weed growth[K]. Members of this genus are rarely if ever troubled by browsing deer[5].

References

  1. F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00

    ↩

  2. Clapham, Tootin and Warburg. Flora of the British Isles. Cambridge University Press 1962-00-00

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  3. Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990-00-00 ISBN 0-9628087-0-9

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  4. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3

  5. Thomas. G. S. Perennial Garden Plants J. M. Dent & Sons, London. 1990-00-00 ISBN 0 460 86048 8

    ↩

  6. Grieve. A Modern Herbal. Penguin 1984-00-00 ISBN 0-14-046-440-9

    ↩1↩2

  7. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

    ↩

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