The Glandora diffusa ‘Heavenly Blue’ is a genus from the borage or forget-me-not family (Boraginaceae ) and is commonly named purple gromwell. The Glandora diffusa ‘Heavenly Blue’ is native to southwestern Europe and northern Africa. In addition to Glandora diffusa ‘Heavenly Blue’ the synonyms Glandora prostrata ‘Heavenly Blue’, Lithodora diffusa ‘Heavenly Blue’ and Lithospermum diffusum ‘Heavenly Blue’ are also used for this plant.
The word “lithodora” comes from Ancient Greek and means “stone gift”, referring to its preferred rocky habitat. “Diffusa” is Latin for “loosely spreading” which refers to the plant's growth habit.
The purple gromwell is a creeping subshrub that thrives in neutral to acidic, well-drained soil and a sunny and sheltered spot. It prefers sandy soil that is not too rich in nutrients. From late spring Glandora diffusa ‘Heavenly blue’ produces stunning, intense blue flowers. The purple gromwell spreads gradually but is easy to restrain. You can cut or pull away the parts where you do not want them.
The Glandora diffusa ‘Heavenly blue’ has dark green, sturdy, hairy leaves. The purple gromwell is ideal for rock gardens, along the edges of your border or as groundcover. The Glandora diffusa ‘Heavenly blue’ is drought and salt tolerant. This subshrub does not cope well with overly wet soil during winter.
Attracts bees: yes
Characteristic: evergreen
Exposure: sun/part shade
Flower colour: blue
Flowering time: April – June
Foliage colour: green
Fragrant flower: no
Hardiness: -20 ºC/-4 ºF
Height: 15 cm/6 inches
Soil: normal/dry