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Lithodora zahnii - plant of the month March 2013




The genus Lithodora consists of seven species of more or less evergreen shrublets. Lithodora is a member of the Boraginaceae family, having small, simple leaves and cymes of tubular to funnel-shaped flowers with five spreading petal lobes. The flowers may be blue or white. L. zahnii 'Azure-ness' is a selected pure blue clone.

Lithodora zahnii comes from southern Greece where it can be found growing on cliffs; the Greek lithodora literally means "stone gift", referring to their preferred rocky habitats.

L. zahnii forms a much branched shrublet to around 30cm in overall height but can grow several metres wide. It usually starts flowering in February, through the summer, than intermittently until mid autumn. It produces linear to narrowly oblong, leathery, glossy green leaves covered in small hairs, which are greyish beneath - this is an adaptation to avoid desiccation in its hot dryish habitats.  It prefers basic to neutral soils; best in a dry wall or in an Alpine House.

The image below was taken in the RHS gardens at Wisley (14/03/13) in the Tufa house, where at least two distinct clones can be seen. Although slow growing, this plant can attain quite large proportions if given some protection from the elements.

Ray Drew