About Asarum europaeum subsp. caucasicum (Duch.) Soó
This subspecies has the scientific name Asarum europaeum subsp. caucasicum (Duch.) Soó. Its prostrate stems are 10–15 centimetres (3.9–5.9 in) long, and each stem bears two reniform leaves with long petioles. The leaves are approximately 10 cm wide, their upper surface is shiny, and they have a pepper-like taste and smell. 2 to 3 stipules are present, arranged in two opposite rows on the stem. The flowers are solitary, terminal, and nodding. The flower tube is formed from fused tepals, ending in 3 petal-like projections that are brownish near their ends and dark purple toward the centre. Each flower has 12 stamens, and flowers emerge in late winter and spring. Asarum europaeum (the parent species of this subspecies) has a wide distribution across Europe. Its natural range extends from southern Finland and northern Russia south to southern France, Italy, Croatia, Serbia, Bosnia and Herzegovina, North Macedonia, and Bulgaria. It does not occur naturally in the British Isles, Scandinavia, northwestern Germany, or the Netherlands. Within Europe, the plant is cultivated outside its natural range in the United Kingdom, Denmark, Sweden, Norway, and the Netherlands. It grows mostly in deciduous woodland or coniferous forests, particularly on calcareous (chalky) soils. Two ecological studies of Asarum europaeum populations have been published: one by Yaroshenko and Nataliia (2022) on ontogenetic and vitality structure in Göttingen Forest, Lower Saxony, Germany, and one by Kovalenko, Klymenko, and Hozhenko (2017) on population analysis in the northeast of Ukraine. Asarum europaeum is quite shade-tolerant, and is often used as groundcover in locations where few other plants will grow. It has received the Royal Horticultural Society's Award of Garden Merit.
