- Author: Susan P Croissant
Native to Italy. A food source for the adult Painted Lady Butterfly and the California Dogface Butterfly. The garden plant grown under this species name is likely a hybrid or polyploid mutation.
"True" C. gymnocarpa is rare, endangered and endemic (indigenous) to the remote island of Capraia (Isola Capraia) in the Tyrrhenian Sea near Naples, close to French Corsica, part of the Tuscan Archipelago. Under Conservation Action law guiding biodiversity conservation in the Tuscan region, it is forbidden to collect any species in this genus. On the IUCN (International Union for Conservation of Nature) red list of endangered species since 2006. Invasive alien plants threatening sub-populations are Carpobrotus acinaciformis (fig-marigold family) and Senecio angulatus (sunflower family), found mostly in Capraia between the cities of Paese and Porto. See photos differentiating garden plant vs. endemic at: http://gimcw.org/plants/Centaurea.gymnocarpa.cfm
For IUCN red list including birds, fish, fungi, reptiles, amphibians, mammals, etc.: http://cms.iucn.org/about/work/programmes/species/who_we_are/ssc_specialist_groups_and_red_list_authorities_directory/. Info on IUCN at: http://www.iucnredlist.org/about/overview#partnership.
This species belongs to the "cineraria" group. It was probably once a single species when the land masses were united. But as islands were formed, new species evolved on each island. Today, there are a number of closely related species of Centaurea in the Mediterranean growing on rocky seaward cliffs. Herbaceous, it colonizes in cracks and fissures of rock faces, growing on acid rocks. Found in association with Linaria capraia and other endemics Silene badaroi and Galium caprarium.
Of the 500 species, only 12 are cultivated. The garden variety is a perennial growing up to 13-ft high, 1-ft wide. Great for cut flowers and wildlife. White/silver felt-like leaves are more finely divided than C. cineraria. The big, fluffy 2" purple flowers bloom in late Spring or Summer, 2-3 at the ends of leafy branches. Full sun or bright shade, very drought tolerant (but can take regular irrigation/moderate water), deer resistant, hardy to 15-20°F. Fast growing in pots or ground, and flowers from seed within 2 years. For best performance, add lime to acid soils. Clay tolerant.
For garden variety, see: https://www.anniesannuals.com/plants/view/?id=2977
One of the many wonderful species that frequent Gabriel Vaturi's collective Mediterranean/Tropical garden, where I was docent at this year's Vallejo Garden Tour.