Culture
Easily grown in organically rich, moderately fertile, evenly moist but well-drained soils in full sun to part shade. Plants appreciate some part shade in the heat of the day in hot summer climates. Plants are more sensitive to drought and heat than common rhubarb. Best growth occurs in USDA Zones 5-7. Plants dislike the hot summer temperatures of the deep South in Zones 8-9. Mulch to keep roots cool and retain moisture. Best propagated by division of rhizomes in early spring. Plant seed in fall.
Noteworthy Characteristics
Rheum australe, commonly called Himalayan rhubarb or red-veined pie plant, is a stout rhizomatous perennial with a large rootstock and thick leafstalks. It is native to grassy slopes in the Himalayas where it typically grows to 4-7’ (occasionally to 9’) tall and to 3-5’ wide. Rounded to broad-ovate to elliptic-oval basal leaves (to 30” long) have wavy margins and cordate bases. Much smaller stem leaves are narrow-ovate. Star-shaped, dark reddish-purple flowers in large, dense, branched panicles (to 8-12” long) bloom in June-July.
Unlike its culinary cousin (Rheum x hybridum) which is the rhubarb grown as a vegetable for harvest of its edible leaf stalks, Himalayan rhubarb is basically grown as an ornamental for enjoyment of its huge rounded leaves and feathery plumes of summer flowers, and/or as a medicinal plant for treating a wide range of human medical problems in the circulatory, digestive, endocrine, respiratory and skeletal systems.
Himalayan rhubarb was formerly known by the synonymous name of Rheum emodi.
Genus name comes from the Greek name for the roots and rhizomes imported from Iran (or genus name comes from the Greek word rha which is the ancient Greek name for the common rhubarb).
Specific epithet comes from the Latin word australis meaning from the south.
Problems
No serious insect or disease problems. Crown rot is a potential problem, particularly if soils drain poorly. Also susceptible to borers, beetles and rhubarb curculio.
Uses
Bold ornamental specimen or accent. Needs a large growing space. Borders. Water margins of streams or ponds. Herbal/conventional medicinal uses.