Caryopteris x clandonensis ‘Dark Knight’ (bluebeard ‘Dark Knight’)

Ceratostigma plumbaginoides (plumbago)

Chionodoxa forbesii ‘Blue Giant’ (glory of the snow ‘Blue Giant’)

Chionodoxa sardensis (Turkish glory of the snow)

Clematis integrifolia (solitary clematis)

Crocus ‘Vanguard’ (crocus ‘Vanguard’)

Echinops bannaticus ‘Blue Glow’ (globe thistle ‘Blue Glow’)

Echinops ritro ‘Veitch’s Blue’ (globe thistle ‘Veitch’s Blue’)

Eryngium x zabelii ‘Big Blue’ (sea holly ‘Big Blue’)

Eurybia macrophylla ‘Twilight’ (big-leaf aster ‘Twilight’)