Lithodora diffusa (16/11/2013, Kew Gardens, London)
Position: Full sun
Flowering period: Late spring to autumn
Soil: Moist, well drained
Eventual Height: 30cm
Eventual Spread: 1.2m
Hardiness: 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
Family: Boraginaceae
Lithodora diffusa is an evergreen shrub with a spreading habit. Its hairy dark green leaves are lanceolate with entire margins, up to 25mm long and 5mm broad. Its blue flowers are five lobed and up to 12mm across.
Lithodora diffusa Flower (16/11/2013, Kew Gardens, London)
Lithodora diffusa, commonly known as Purple Gromwell, is native to south and west Europe. Lithodora diffusa is synonymous with Lithospermum diffusum.
The etymological root of the binomial name Lithodora is derived from the Greek lithos meaning ‘stone’ and doma meaning ‘gift’. Diffusa is from the Latin meaning ‘spreading out’.
The landscape architect may find Lithodora diffusa useful as a free flowering ground cover shrub suitable for acidic soils.
Ecologically, Lithodora diffusa flowers are attractive to pollinating insects.
The Royal Horticultural Society has given the varieties Lithodora diffusa ‘Heavenly Blue’ and Lithodora diffusa ‘Grace Ward’ their prestigious Award of Garden Merit in 1993.
Lithodora diffusa Leaf (16/11/2013, Kew Gardens, London)
Lithodora diffusa prefers moist, fertile, humus rich, well-drained soils. It prefers an acid to neutral pH of soil. It dislikes wet soils.
Lithodora diffusa requires little maintenance. If required, pruning should be carried out after flowering.
