Aster x frikartii 'Monch':
Soft lavender blue flowers in late summer. Very early flowering and shorter than many asters at about 80cm. Easy and reliable.
Calamintha nepeta 'Blue Cloud':
Spikes of small, soft blue flowers above mounds of minty scented green leaves. Loved by bees and butterflies. Hardy. Up to 30cm.
Echinops ritro (Globe Thistle):
Blue globes held above stout grey green foliage. Attractive to bees. Likes well drained soil and plenty of sun. Hardy. Up to 1m.
[Collect Only]
Eryngium x zabelii 'Big Blue (Sea Holly 'Big Blue):
Large electric-blue thimble-shaped flowers with a spiky collar and silver-green foliage. Long flowering and bee-friendly. Hardy. Up to 75cm
[Collect Only]
Salvia uliginosa (Bog Sage):
Branched stems of clear blue flowers and lance-shaped leaves. Needs a sunny spot but with moist soil. Late flowering. To 2m.