Asarum asaroides

Around 50 species of Asarum grow in Japan and the Ryukyu Islands, many of them found only there. They include A. asaroides, which occurs in south-west Honshu and Kyushu.

The spotted and mottled leaves are broadly ovate (egg-shaped) to roughly triangular in outline and up to 12 cm long. They persist throughout much of the year but the main growing period is during spring and summer.

The dull, dark purplish-green flowers appear in early spring, and have a pear-shaped tube 2–2.5 cm long, and three spreading, rounded to triangular lobes. Around the mouth of the tube, the perianth (sepals and petals) lobes are wrinkled, these ridges being lighter purple or crested with white. The flowers have also been described as 'perfumed somewhat like a ripe apple’ and ‘large as a walnut’.

Asarums have been cultivated in Japan for hundreds of years. Some believe they offer protection from earthquakes and storms if planted at the front of houses or hung from the eaves.

Although Asarum asaroides can tolerate a few degrees of frost, it is best grown in a cold frame to keep off rain in the winter and provide some protection during particularly cold spells. Use an acidic, humus-rich, free-draining soil mix and place the rhizomes just below soil level. During the winter keep the soil just moist but once growth begins in spring, increase watering and never let the soil dry out throughout spring and summer. If this species is tried in the open garden, plant it in a cool, shady, sheltered spot.

This is a slow-growing plant but older clumps can be carefully divided in spring, by cutting off portions of the rhizome with roots and a growing point. If seed is produced it should be collected and sown immediately, before it dries out. Germination will usually occur in early spring but may take over a year.

Asarum asaroides can be seen in the Davies Alpine House at Kew when in flower.

Spirit-preserved of Asarum asaroides are held in Kew’s Herbarium, where they are available to researchers, by appointment. The details of one of these can be seen on-line in the Herbarium Catalogue.

Search Kew’s science databases for more information on this species

Visit Kew’s Davies Alpine House

Read the Alpine & Rock Garden Team blog

Buy 'Alpines from Mountain to Garden' by Richard Wilford

Curtis’s Botanical Magazine (Wiley-Blackwell)