We have found 11 plants that meet your criteria.

Agapanthus africanus African Lily Globes of blue flowers in late summer £6.84 Buy
Artemisia ludoviciana 'Valerie Finnis' Valerie Finnis Artemisia Very drought tolerant £5.37 Buy
Artemisia 'Powis Castle' Wormwood Silvery, aromatic foliage £5.37 Buy
Iris sibirica 'Perry's Blue' Siberian Flag Looks great planted in bold clumps £5.86 Buy
Iris sibirica 'Snow Queen' Beardless Siberian Iris (syn. I.... Great for adding vertical interest £5.86 Buy
Phlomis fruticosa Jerusalem Sage Evergreen shrub with whorls of yellow flowers £5.86 Buy
Phlomis tuberosa 'Amazone' Jerusalem Sage Whorls of lilac flowers and architectural seedheads £6.84 Buy
Agapanthus africanus 'Albus' African Lily White globes of trumpet-shaped flowers £6.84 Buy
Hebe rakaiensis shrubby Veronica Evergreen with neat, domed shape and white flowers £7.82 Buy
Hebe 'pinguifolia Pagei' Shrubby Veronica Clusters of white flowers and blue-green foliage £7.82 Buy
Hebe 'Red Edge' Shrubby Veronica Small hebe with lilac flowers £7.82 Buy