Exacum is an evergreen, compact and well-branched member of the Gentianaceae grown for its summer flowering. It prefers a south-facing, sheltered site in full sun with neutral, moist loam. Classed H1c (tender), it is not frost-hardy and is best used in pots or locations where it can be protected over winter.

Exacum is a well-branched evergreen that flowers June to September and suits south-facing pots or sheltered borders in neutral, moist loam.

Exacum

Exacum (Gentianaceae) | Summer-flowering for Pots

Gentiana 'Barbara Lyle' is a mat-forming, trailing gentian that forms low clumps and spreads as a ground cover. It produces summer flowers from June to September above semi-evergreen to deciduous foliage. Plant it into loam that is acid to neutral and kept moist but well-drained, in full sun or partial shade. Hardy (H5), it suits south-, east- or west-facing sites and tolerates both exposed and sheltered positions.

Gentiana 'Barbara Lyle' is a mat-forming gentian that flowers June to September and prefers moist, well-drained loam in full sun or partial shade.

Gentiana 'Barbara Lyle'

Gentiana 'Barbara Lyle' | Trailing mat-forming gentian

Gentiana asclepiadea 'Nana' is a mat-forming gentian in the family Gentianaceae that forms low, trailing clumps. It bears trumpet-shaped, deep blue flowers from June to September. The foliage is semi-evergreen and the plant remains in compact tufts. It prefers moist but well-drained loam in full sun or partial shade.

Gentiana asclepiadea 'Nana' forms low, mat-forming clumps with deep blue, trumpet-shaped flowers from June to September.

Gentiana asclepiadea 'Nana'

Willow Gentian (Gentiana asclepiadea 'Nana') | Blue blooms

Gentiana makinoi 'Marsha'PBR is a mat-forming gentian that produces trailing, tufted clumps. Its foliage can be semi-evergreen to deciduous and it suits full sun or partial shade. It prefers loam that is moist but well-drained and is rated H5 (hardy). Flowering occurs from June to September.

Gentiana makinoi 'Marsha'PBR is a mat-forming gentian flowering June to September, for loam soils in sun or partial shade.

Gentiana makinoi 'Marsha'PBR

Gentiana makinoi 'Marsha'PBR | Mat-forming Gentian

Swertia petiolata is a member of the gentian family (Gentianaceae) that favours moist to wet ground. It reaches about 0.6 m in height and tolerates sandy, loamy or clay soils. Flowering occurs from July to September. The species is rated H6 for UK hardiness and corresponds to USDA zones 6–9.

Swertia petiolata prefers moist to wet sandy, loamy or clay soils and flowers from July to September.

Swertia is a genus in the gentian family containing plants sometimes referred to as the felworts. Some species bear very showy purple and blue flowers.