Centaurea acaulis aka Stemless Star Thistle

Centaurea acaulis belongs to Asteraceae, the daisy family. It is a perennial, which means it lives for more than two years. Its native range lies in North Africa. It has also become naturalized in Spain, growing beyond gardens. It is not native to Britain or Ireland. Plants For A Future lists it for use in cultivated beds. The supplied sources give no firm height or spread. They give no leaf, stem, or flower colour details for this species. The RHS describes the genus, not this species’ form. Those broad traits cannot show what this plant looks like.

Its flowers have both male and female parts. Bees and flies help pollinate them, as do butterflies and moths. The plant is also self-fertile. The evidence gives no bloom months or fruit details. Plants For A Future lists sand, loam, and clay as suitable soils. It states that the plant needs soil that drains well. Its account also allows for soil with few nutrients. The stated soil range spans mildly acid to strongly alkaline. That source says the plant cannot grow in shade. It prefers dry or moist soil and can withstand drought.

Its hardiness is unclear, so it has no firm winter rating. Plants For A Future says it knows little about this species. Its separate growing notes draw on the whole genus. Those notes do not support firm care claims for this species. They do not show its frost limits or whether it resists deer. The sources give no pest or disease details for this species. They give no growth rate or time to full size. These gaps limit how well gardeners can plan where to place it.

Plants For A Future lists three ways to grow new plants. These are seed, division, and basal cuttings, taken from the base. It advises sowing seed in a cold frame during April. Young plants stay in that shelter through their first winter. They go out in late spring or early summer, after expected frosts. Its guide places division in autumn and basal cuttings in spring. The roots yield a yellow dye, the only stated practical use. That source knows of no edible or medicinal uses. It also reports no known hazards. That wording does not prove safety for people or pets. Its record does not flag the species as a weed.