Short-lived perennial, often grown as an annual or biennial, from the Asteraceae family, this knapweed is endemic to the island of Capraia, in the Tyrrhenian Sea, off the coast of Tuscany, where it grows on the wind-exposed coastal cliffs and rocky slopes.
In cultivation, it develops a broad and cascading dome shape, sometimes reaching a spectacular spread, up to 80 to 120 cm in height and as much in spread. The arching stems, covered with a dense white tomentum, bear deeply pinnatisect leaves with narrow, sharp segments, entirely covered with an intense silvery white felt on both sides. The overall effect is that of a woolly and architectural mass, almost pure white, which captures the light in a striking way.
The pink-purple flowers appear late in the season but remain secondary: it is primarily for its foliage that the plant is cultivated, as a centerpiece in compositions with contrasting colors or textures.
In its natural habitat, flowering extends from May to July.
It requires full absolute sun and perfectly drained soil, poor to moderately fertile. It fears excess winter moisture much more than cold. In regions with mild winters, it can behave as a perennial; elsewhere, precautionary cuttings at the end of summer are advised.