About
Mertensia maritima, the oysterplant, is a spreading, prostrate, sea-coast perennial producing fleshy, blue-grey-green leaves and branched clusters of bright-blue, bell-shaped flowers opening from pink buds in early summer. An attractive and ornamental native plant for a sunny, very well-drained, coastal rock garden.
About the genus
Mertensia are clump-forming herbaceous perennials with grey-green or blue-green leaves and pendant, tubular or narrowly bell-shaped, blue flowers in spring and summer. Grown in cool, moist, humus-rich borders and woodland gardens.
Growing conditions
SunlightFull sun, Partial shade
Soil typeSand
Soil pHAcid, Alkaline, Neutral
Soil moistureWell-drained
AspectWest-facing, East-facing
ExposureSheltered
UK hardinessH5
Plant details
Plant typeHerbaceous Perennial
HabitTrailing
FoliageDeciduous
HeightUp to 10 cm
Spread0.1-0.5 metres
Time to full height2-5 years
Suggested usesCoastal, Cottage and informal garden, Gravel garden, Patio and container plants
Native toNorthern Hemisphere
Care notes
CultivationGrow in sharply-drained, gritty soil with low fertility in full sun with some midday shade
PruningCut back after flowering
PropagationPropagate by seed sown in containers in a cold frame in autumn; keep young plants shaded and do not allow the soil to dry out. Divide plants carefully as new growth begins in spring
Pest resistanceMay be susceptible to slugs and snails
Disease resistanceGenerally disease-free