Marrubium supinum

Perennial of the Lamiaceae family, endemic to the Iberian Peninsula, where it occupies rocky limestone slopes, cliffs, and dry, sunny screes, mainly in the mountainous regions of central and southern Spain, at altitudes between approximately 800 and 2,000 meters.

It forms sprawling and prostrate clumps, rarely upright, reaching 20 to 35 cm in height, with stems that elongate by leaning on the rocky substrate. The foliage is densely tomentose, of a bright silvery-white, with oval crenate leaves almost disappearing under their woolly covering; this intense whiteness is one of the most striking features of the species, particularly visible when the plant cascades over a limestone rock.

The flowers, pink-lilac to pale pink-mauve, are grouped in tight whorls arranged along the stems, each whorl surrounded by whitish spiny bracts that enhance the contrast with the colorful corollas. In its natural habitat, it blooms from May to July. In cultivation, it generally blooms in June.

It requires full sun and a very well-drained, poor, and preferably limestone soil; it dreads stagnant winter moisture. Its hardiness is adequate down to about -12°C. It finds its best place in a dry rock garden, wall, or Mediterranean gravel garden.