We have found 10 plants that meet your criteria.

Siberian Flag ‘Iris sibirica Perry's Blue’ Looks great planted in bold clumps £5.99 Buy
Price Pruned
Lavender ‘Lavandula angustifolia Munstead’ A compact variety with blue-purple flowers NOW £4.99 Buy
Price Pruned
Perennial Phlox ‘Phlox paniculata Blue Paradise’ Fragrant violet flowers all summer NOW £5.49 Buy
Common Lilac ‘Syringa vulgaris Katherine Havemeyer’ Wonderful scented lavender-purple flowers £9.99 Buy
Price Pruned
Butterfly Bush ‘Buddleja Lochinch’ Fragrant violet-blue flowers all summer NOW £5.99 Buy
Price Pruned
Clematis (Group 3) ‘Clematis Betty Corning’ Pale lilac nodding bells with a delicate fragrance NOW £7.99 Buy
Bearded Iris ‘Iris Blue Rhythm’ Tall variety with cornflower-blue flowers £6.99 Buy
Bearded Iris ‘Iris Jane Phillips’ A popular variety with blue flowers £6.99 Buy
Rosemary ‘Rosmarinus officinalis Miss Jessopp's Upright’ Lavender-blue flowers £5.99 Buy
Price Pruned
Sweet Violet ‘Viola odorata’ Sweetly fragrant flowers NOW £4.99 Buy