Rheum nobile

Rheum nobile, or Sikkim rhubarb, belongs to the Polygonaceae family. It is a perennial, a plant that lives for years. Kew gives its native range as Afghanistan to southern Tibet and northern Myanmar. PFAF also lists Bhutan, Nepal, and Sikkim in India. It grows in cold subalpine or subarctic regions. Wild plants grow on rock ledges and open mountain slopes. These sites lie around 13,120–14,760 feet [4,000–4,500 metres] above sea level.

In gardens, it grows about 5 feet [1.5 metres] tall. It spreads about 3.3 feet [1 metre] wide. PFAF values it for its looks in garden beds. Its size and mountain roots help shape its garden role. The supplied species records say little about leaf shape. They give no bark or stem colour for this species. It blooms from July to August. Each flower has both male and female organs. Wind carries the pollen. Seeds ripen from August to September.

This plant needs deep, rich soil with plenty of humus. The soil should stay moist but let excess water drain. Loam and heavy clay both suit it. It grows in soil that is mildly acid or mildly alkaline. Neutral soil suits it too. Grow it in sun or part shade. PFAF lists USDA zones 6–9 and hardiness near 5°F [−15°C]. Yet its hardiness does not make it easy to grow. PFAF reports great trouble growing it in Britain. Its records name no specific pest or disease problem.

You can grow new plants from seed. PFAF advises sowing in autumn in a shaded cold frame. You can also sow in a cold frame in spring. Move seedlings to their own pots when large enough to handle. Keep them under shelter through their first winter. Plant them outside the next spring. You can divide plants in early spring or autumn. Each piece needs at least one growth bud. Keep small pieces under cover for a time before planting out.

People in its native range eat the leaf stalks raw or cooked. The stalks taste sour and serve as a vegetable. This use covers the stalks, not the leaf blades. PFAF also lists past uses of roots and flowering stems as medicine. People used them to aid digestion, loosen stools, and clear fluids. These records describe past practice, not proof of safe treatment. The supplied evidence does not confirm whether this species is toxic.