Aristolochia debilis

Aristolochia debilis, or Ma Dou Ling, belongs to the Aristolochiaceae family. This climbing perennial comes from China and central and southern Japan. Its Japanese range includes Honshu, Shikoku, and Kyushu. It grows in lowland meadows and thickets beside roads. Kew places it within a subtropical climate range. It is not native to Britain or Ireland.

Plants reach about 3.3 feet (1 metre) tall and wide. The climbing habit gives it a different form from upright perennials. PFAF lists cultivated beds as a place to grow it. Flowers appear from July to August. Each flower has both male and female organs. Flies pollinate the flowers, and seeds ripen from September to October. The medicinal records also refer to fruit with a capsule.

Grow this species in sun or partial shade. It prefers moist soil that drains well. Rich loam suits it, though ordinary garden soil can also work. PFAF lists sandy, loamy, and clay soils as suitable. It accepts mildly acid, neutral, and mildly alkaline conditions. Its cold tolerance needs care when choosing a site. PFAF lists USDA zones 7–10, but also reports tolerance only to about 23°F (−5°C). The same source describes it as poorly hardy in Britain. Those accounts do not give a single clear cold limit.

Seeds offer one way to raise new plants. Sow fresh seed in a greenhouse once it ripens in autumn. Stored seed may benefit from three months of cold treatment at 41°F (5°C). PFAF also advises soaking stored seed for 48 hours before surface sowing. Germination can take one to three months at 68°F (20°C). Keep young plants in a greenhouse through their first winter. Plant them outside after the last expected spring frost. Autumn division and winter root cuttings offer other ways to propagate it.

Safety matters more than its reported food uses. PFAF records cooked leaves as edible, but urges caution. The plant contains aristolochic acid, which can harm kidneys and cause cancer. Reports of edible leaves do not establish that eating them is safe. Traditional medicine has used its fruit, capsules, and roots. These records include uses for coughs, asthma, pain, and high blood pressure. They do not remove the toxicity risk or justify home treatment.