Maltese Star Thistle
Centaurea melitensis
Family: Asteraceae or Compositae
What it is like
Centaurea melitensis is a ANNUAL growing to 0.5 m (1ft 8in). See above for USDA hardiness. It is hardy to UK zone 7. It is in flower from July to September, and the seeds ripen from September 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. It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought.
Height (m): 0.5
Where it is found
Wasteplaces and roadsides.
Mediterranean region, eastwards to Greece and Tunisia. A not infrequent casual in Britain.
Conservation Status: This taxon has not yet been assessed.
Countries/locations it is found in
How it is used
Food
Rating: 0
Medicine
Rating: 1
The plant is used in the treatment of the kidneys.
Other
Rating: 0
How it is grown
We do not have information on this species, but the following notes are based on the closely related C. solstitialis. Succeeds in ordinary garden soil. Prefers a well-drained fertile soil and a sunny position. Tolerates dry, low fertility and alkaline soils. A good bee and butterfly plant the flowers are rich in nectar. 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 into their permanent positions in the summer. If you have sufficient seed it can be sown in situ in the spring, and an autumn swing in situ might also be worth trying.
Best place to grow: Cultivated Beds;
Habit: Annual
Hardiness: 6-9
Growth:
Soil: Light (sandy), medium, heavy (clay)
Shade: No shade
Moisture: Dry, moist
Things to keep in mind
This plant can be weedy or invasive. US: Nevada - Noxious weed. New Mexico - Class B noxious weed.
Its other names
Local names
Maltese star-thistle, tocalote or tocolote, spotted knapweed, Malta starthistle.