This stunning, low growing perennial produces an abundance of intense, true blue star shaped flowers that create a vivid carpet of colour in late spring and early summer. Lithodora diffusa ‘Heavenly Blue’ is perfect for brightening rockeries, borders, and containers, with its striking blooms standing out against dark green foliage.

Lithodora diffusa ‘Heavenly Blue’, commonly known as Gromwell, is loved for its rare, almost electric blue flowers and its neat, spreading habit. It forms a dense mat of evergreen foliage, making it ideal for ground cover and for softening the edges of paths, walls, and raised beds.

Perennial

Low growing, Spreading, Evergreen

Flowers: May – July

Foliage: Year round

Scientific Name
Lithodora diffusa ‘Heavenly Blue’ (lithodora refers to stone gift, linked to its traditional medicinal uses)

Synonyms
Sometimes previously classified under Glandora diffusa

Common Name
Gromwell

Origin
Native to southwestern Europe, particularly Spain and Portugal

Pruning Tips
Trim lightly after flowering to maintain a neat shape and encourage fresh growth

Wildlife Value
Attracts bees and other pollinators

Positioning
Full sun to partial shade in a sheltered position. Ideal for rockeries, borders, and containers with excellent drainage

Water
Keep soil consistently moist but well drained, especially during dry periods. Avoid letting it dry out completely

Soil
Acidic to neutral, well drained soil. Prefers sandy or gritty conditions and does not tolerate lime rich soils well

Food
Feed lightly in spring with an ericaceous fertiliser if needed

Pet-safe
Generally considered non toxic to pets

Sprouts Top Tips
Perfect for adding a rare true blue tone to your planting. Pair with softer pinks or whites for contrast, and always ensure excellent drainage to keep it thriving.