Sub-shrub of the Boraginaceae family, Lithodora zahnii is a species endemic to southern Greece, known from a very restricted area in the southeast of the Peloponnese, in the region of Kalamata. It grows on rocks and rocky limestone garrigues, in full light, in a hot and dry Mediterranean climate.
It forms a dense and rounded bush, reaching 30 to 40 cm in height and significantly widening with age. The foliage is particularly remarkable: the narrow, linear leaves, arranged in a star around the stems, are a dark green traversed by a very clear white median line, which gives the plant a geometric and silvery texture immediately recognizable outside of flowering.
The flowers, with five spreading lobes, open in a soft and bright sky blue, with buds tinged with violet. They are produced in great abundance and completely cover the foliage at the peak of flowering. In its natural habitat, its flowering extends from March to May. In cultivation under a temperate climate, it generally blooms from April to June.
It requires perfect drainage, poor and calcareous soil, and a warm and sunny exposure. It does not tolerate prolonged humidity in winter well and requires protection in regions with cold and rainy winters.