Centaurea jacea
Brown knapweed
Common names: Meadow knapweed, Hardheads
At a glance
- Light
- Full sun
- Pot size
- from 10 l
- Lifespan
- Perennial
- Flowering
- Jun–Sep
- Hardiness
- Hardy down to −30 °C
- Water need
- Low
- Origin
- Native to Germany
Photo: de:Benutzer:Tigerente · CC BY-SA 3.0 · Source
This description was machine-translated.
Description
Brown knapweed, botanically Centaurea jacea, grows in Central Europe on lean meadows, semi-dry grasslands and along roadsides. It is an undemanding native meadow flower. Branched stems rise from a sturdy rootstock to 30 to 80 cm in height. From June to September, purple-pink flower heads 2 to 4 cm wide open, and their bracts bear brown, papery appendages. Wild bees, hoverflies and butterflies visit them readily, and in autumn birds pick out the seeds. In the garden, it suits flower meadows, herbaceous edges, near-natural perennial beds and gravel areas. It self-seeds abundantly, which is desirable in a meadow but requires watchful management in a bed. For meadow planting, use regional seed from your area of origin.
Care instructions
Plant brown knapweed in spring or September in a sunny spot with permeable, rather lean soil, leaving about 40 cm of spacing. In the first year, water during dry spells; later it manages with rainfall and tolerates dry summers. No fertilizer is needed, as it makes the plant leggy and soft. Cutting off spent flowers in summer extends flowering and reduces self-seeding. Leaving the seed heads standing produces new plants the following year, and birds find food on them in winter. Cut the old stems back close to the ground in early spring. Typical mistakes are overly rich, permanently wet soil and planting too closely, which causes the plant to topple over.
The care notes were machine-translated from German.
Garden year
SowingApr–Jun, Sep
FloweringJun–Sep
Germination
- Soil temperature
- from 8 °C, ideally 18 °C
- Days to sprout
- 10 to 21 days
- Light
- Sprouts in light or dark
- Sowing depth
- 0.5 cm
- How to start
- Sow straight into the bed
Soil & site
Soil pH
Soil type
well-drained, loamy, lean, dry
Brown knapweed is happy with almost any garden soil, as long as it is free-draining and not too rich. It feels most at home on dry to moderately moist, loamy or stony ground, like that of unimproved meadows and verges, even in shallow spots with little soil over rock. Lime doesn't bother it, and slightly acidic soil is fine too. It won't tolerate permanently wet, heavy soils, and in very nutrient-rich soil it grows tall and flops over.
Feeding
Light feeder
Brown knapweed needs no fertiliser. On lean soil it stays sturdy and flowers for a long time, while nutrient-rich soil makes the stems long and soft. In a container, it is also enough to swap the top layer of soil for fresh, free-draining soil in spring.
Overwintering
Brown knapweed is fully hardy and needs no protection in the bed. The top growth dies back in winter and the plant shoots again from the rootstock in spring. More important than frost is that no water stands around the roots. In a container, place the pot against a sheltered house wall and protect the root ball with horticultural fleece or hessian in hard frost.
Propagation
Methods
- From seed
- Division
The easiest way to propagate brown knapweed is by sowing. From mid-April to mid-June, scatter the seeds on lightly scratched-up soil and just press them in, at most covering them with a very thin layer of soil. With even moisture they come up after 2 to 3 weeks. Sowing in September works too. In spring or autumn you can divide larger clumps with a spade. On open ground the plant self-seeds; it is best to move seedlings while they are still small.
Companion planting
Companion planting is partly traditional gardening lore. Where the reason is known, it is given.
Some of these explanations were machine-translated.
For your garden
Grow Brown knapweed yourself
Gartenkern tells you when frost is coming, when to sow and when to harvest, for your location.
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