Stokesia laevis is a perennial in the daisy family that forms compact clumps bearing daisy-like flowerheads from July to September. Flower colours are most often blue or purple, with white forms and a range of cultivated colours also available. It originates from the southeastern United States and favours well-drained loamy or sandy soils. Plants perform best in full sun or light shade and are classed as hardy (H5) in the UK.

Stokes' aster (Stokesia laevis) produces daisy-like flowers from July to September and suits well-drained soils in sun or partial shade.

https://en.wikipedia.org/wiki/Stokesia_laevis

Stokesia laevis

Stokes' aster | Stokesia laevis

Stokesia laevis 'Alba' is a perennial in the daisy family that carries white summer flower heads from July to September. It suits a sunny position but will tolerate some light shade and prefers well-drained loamy or sandy soil with neutral to slightly acidic pH. Rated H5, it is hardy in much of the UK when planted in a free-draining site. The flowers are produced on stems above the foliage and work well for cutting.

Stokes' aster 'Alba' (Stokesia laevis 'Alba') is a hardy H5 perennial with white flower heads that bloom July to September in well-drained soil.

Stokesia laevis 'Alba'

Stokes' aster 'Alba' | Stokesia laevis 'Alba'

Stokesia laevis 'Amethyst' is a herbaceous perennial in the daisy family that carries its main display from July to September. It forms a well-branched, evergreen clump suited to sheltered, south-, west- or east-facing positions. It prefers loam or sandy soils that are moist but well-drained and range from acid to neutral. Use it in cottage borders, wildlife plots, containers and as a source of cut flowers.

Stokes' Aster (Stokesia laevis 'Amethyst') flowers from July to September and prefers full sun in sheltered, south- to west-facing sites with moist.

Stokesia laevis 'Amethyst'

Stokes' Aster | Stokesia laevis 'Amethyst'

Stokesia laevis 'Blue Star' is a perennial in the daisy family Asteraceae, valued for its summer flower display from July to September. It originates from the southeastern United States and performs best in full sun or partial shade. Plant in well-drained sandy or loamy soils that are acidic to neutral and kept moist but not waterlogged. Suited to borders, rock gardens and containers where drainage can be controlled.

Stokes' aster 'Blue Star' is a fully hardy perennial that flowers from July to September and suits borders, rock gardens and containers.