Common Star Thistle, Red star-thistle
Centaurea calcitrapa
Family: Asteraceae or Compositae
What it is like
Centaurea calcitrapa is a BIENNIAL growing to 0.6 m (2ft). It is in flower from July to September, and the seeds ripen from August to October. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees, flies, Lepidoptera (Moths & Butterflies). The plant is self-fertile. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very alkaline soils. It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought.
Height (m): 0.6
Where it is found
Waysides and waste places on sandy, gravelly and chalky soils.
Europe. Probably introduced in Britain.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 1
Leaves and young stems - raw or cooked.
Medicine
Rating: 1
The powdered seeds are drunk as a remedy for stone. The powdered root is said to be a cure for fistula and gravel.
Diuretic: Acts on the kidneys, promoting the flow of urine.
Other
Rating:
How it is grown
Succeeds in ordinary garden soil. Prefers a well-drained fertile soil and a sunny position. Tolerates dry, low fertility and alkaline soils. Members of this genus are rarely if ever troubled by browsing deer.
Propagating it: 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 in the summer. If you have sufficient seed, it can also be sown in situ during August/September.
Best place to grow: Cultivated Beds;
Habit: Biennial
Hardiness: 0-0
Growth:
Soil: Light (sandy), medium, heavy (clay)
Shade: No shade
Moisture: Dry, moist