We have found 12 plants that meet your criteria.

Michaelmas Daisy ‘Aster turbinellus’ Sprays of violet blue flowers £5.99 Buy
Cranesbill ‘Geranium Brookside’ Deep blue flowers and long flowering seasons £5.99 Buy
Russian Sage ‘Perovskia Blue Spire’ Violet-blue flowers and silvery foliage. Great planted en masse £7.99 Buy
Cranesbill ‘Geranium wallichianum Buxton's Variety’ Late flowering, with soft, blue-mauve flowers £6.99 Buy
Russian Sage ‘Perovskia abrotanoides’ Silvery white aromatic foliage with long lasting blue flowers £7.99 Buy
Price Pruned
Russian Sage ‘Perovskia atriplicifolia Little Spire’ A shorter form of the popular Russian sage NOW £7.99 Buy
Price Pruned
Greater Periwinkle ‘Vinca major’ Elegant blue-violet flowers NOW £4.99 Buy
Greater Periwinkle ‘Vinca major Variegata’ Large, bright blue flowers £5.99 Buy
Lesser Periwinkle ‘Vinca minor’ Superb ground cover £5.99 Buy
Lesser Periwinkle ‘Vinca minor Argenteovariegata’ Creamy-white leaves £5.99 Buy
Price Pruned
Periwinkle ‘Vinca minor Illumination’ Brand new introduction NOW £5.99 Buy
Price Pruned
Periwinkle ‘Vinca difformis’ Perfect for underplanting in shady spots NOW £5.99 coming soon