We have found 40 plants that meet your criteria.

Price Pruned
Mexican Giant Hyssop ‘Agastache Blue Fortune’ Spires of lilac flowers and aromatic leaves NOW £5.49 Buy
Michaelmas Daisy ‘Aster turbinellus’ Sprays of violet blue flowers £5.99 Buy
Michaelmas Daisy ‘Aster x frikartii Monch’ Lavender-blue, daisy flowers £5.99 Buy
Lesser Catmint ‘Calamintha nepeta subsp. nepeta Blue Cloud’ Aromatic leaves and blue flowers £5.99 Buy
Price Pruned
Milky Bellflower ‘Campanula lactiflora Pritchard's Variety’ Masses of bell-like lilac flowers NOW £4.99 Buy
Price Pruned
Hardy Plumbago ‘Ceratostigma willmottianum’ Excellent red autumn foliage NOW £4.99 Buy
Sea Holly ‘Eryngium x zabelii Jos Eijking’ Spiny metallic-blue flowers in late summer £7.99 Buy
Cranesbill ‘Geranium Brookside’ Deep blue flowers and long flowering seasons £5.99 Buy
Catmint ‘Nepeta subsessilis Cool Cat’ Lavender-blue flowers. Great for a herb garden £5.99 Buy
Catmint ‘Nepeta subsessilis Washfield’ Pretty catmint with bright blue flowers £5.99 Buy
Catmint ‘Nepeta x faassenii’ Loose drifts of lavender flowers. Great for edging £5.99 Buy
Catmint ‘Nepeta x faassenii Kit Cat’ A dwarf variety with purple flowers £5.99 Buy
Beards Tongue ‘Penstemon Jean Grace’ Stunning mediterranean blue flowers £5.99 Buy
Russian Sage ‘Perovskia Blue Spire’ Violet-blue flowers and silvery foliage. Great planted en masse £7.99 Buy
New
Spanish Sage ‘Salvia lavandulifolia’ A great alternative to common sage £4.99 Buy
Sage ‘Salvia patens’ Large, stunning blue blooms £5.99 Buy
Bog Sage ‘Salvia uliginosa’ Intense blue flowers £5.99 Buy
Price Pruned
Pincushion Flower ‘Scabiosa Butterfly Blue’ Delightful pale blue pincushion flowers NOW £5.49 Buy
Michaelmas Daisy ‘Aster sedifolius nanus’ A small plant that has big impact £5.99 Buy
Cranesbill ‘Geranium wallichianum Buxton's Variety’ Late flowering, with soft, blue-mauve flowers £6.99 Buy