This grower is sure of this plant identification.
Photos often don't show flower colour properly: deep gentian-blue (think deepest sky-blue in the evening, with a slightly paler centre). Flowers for months (unlike gentians!). Was 50cm across, but we cut it hard back last year.
Lithodora diffusa ‘Heavenly Blue’. This has elliptical, mid green leaves with a mass of funnel-shaped, deep blue flowers in late spring to mid summer.
Trim stems after flowering.
Walls, rock garden
Italics = data drawn from parent genus or speciesView Full Plant Finder Record