Aster 'Little Carlow' (Syn. Symphyotrichum 'Little Carlow' (cordifolium hybrid)): Large sprays of small purplish blue flowers in autumn. Very reliable, easy to grow perennial. Up to 1m.

Baptisia australis (Indigo weed): Spires of lipped indigo flowers over olive-green foliage. Flowering height 1.2m. [Collect Only]

Campanula lactiflora 'Prichards Variety' (Milky bellflower 'Prichards Variety'): Clusters of warm blue flowers on tall stems in mid-summer. To 1m. Hardy.

Echinops bannaticus 'Blue Globe' (Globe thistle): Tall upright stems of bright blue globe flowers above clumps of spiny, grey-green leaves. Bee-friendly. Hardy. Up to 1.2m.

Phlox paniculata 'Blue Paradise' (Phlox 'Blue Paradise'): An attractive form with bright blue-purple heavily scented flowers. Good for cutting. Hardy. Up to 1.2m.

Salvia patens 'Cambridge Blue': Beautiful Salvia with pale blue two-lipped flowers flowering in late summer. Needs a sunny, sheltered position and protect with mulch.To 1m.