Marrubium incanum

The Marrubium incanum, also known as Grey Horehound or White Horehound, is a plant related to the sage family (Lamiaceae) native to Southern Europe. It is a drought-tolerant perennial with silky, bright foliage in shades of gray, silver, and white. It harmonizes perfectly with the rather discreet but appreciated white flowering, which is attractive to bees. It is a beautiful plant for dry gardens, rockeries, and arid slopes, providing structure throughout the year.

White Horehound is native from the Adriatic coast to southern France, Sicily, and the Balkan Peninsula. It can be found in dry and poor pastures frequented by sheep, up to an altitude of 1200m. It is a plant that thrives in rocky, gravel-rich or rocky soils, tolerating drought and nutrient-poor soils very well. Its hardiness is estimated at -12/-15 °C in well-drained soil.

The plant, which somewhat resembles a large greyish mint, quickly forms a clump of upright, leafy stems. It reaches a height of 35 to 55 cm and a width of 50-55 cm. These square-sectioned, sparsely branched stems are covered in a light fuzz. They bear thick, oval, wavy-edged leaves with silver-gray colour on the upper side and white, silky undersides, measuring 2 to 5 cm in length. They have a slightly aromatic scent when crushed. The flowering, nectariferous and melliferous like that of many Lamiaceae, takes place from May to July. It may be earlier in the south and later elsewhere. In the axils of the small leaves that line the upper part of the stems, whorls or staggered clusters of small bilabiate flowers form. Their colour, pale and discreet, ranges from pale lilac gray to greenish white. The foliage persists more or less in winter. Towards the beginning of March, the stems become bare. When pruned, the plant vigorously regrows from its stump. The new growth quickly forms a large ball.

Marrubium incanum is a very interesting perennial for low-maintenance gardens, particularly for its highly ornamental foliage. It is ideal in dry and hot areas, and is very useful in rockeries, borders, and sun-drenched flower beds where it forms dense and bright masses. It is an excellent companion for Mediterranean plants such as oreganos, thymes, lavenders, and rockroses. Its light foliage also harmonizes well with the colourful flowering of shrubby salvias and the delicacy of gauras.