Symphytum asperum aka Rough Comfrey

Symphytum asperum belongs to the borage family, Boraginaceae. This perennial lives for more than one year. Its names include prickly comfrey, rough comfrey, and Persian comfrey. Its native range starts in northeast Türkiye. It runs through the Caucasus into northern and northwest Iran. It grows in temperate climates but is not native to Britain. Plants now grow beyond gardens in southern Canada and northern America.

This plant grows upright, with a coarse form and hairy growth. It stands about 3–4 feet (0.91–1.22 metres) tall. It can spread to 4 feet (1.22 metres) wide. Creeping stems below ground, called rhizomes, help it form colonies over time. Its dark green leaves range from oval to broad and tapered. They grow about 2–8 inches long and have stiff, prickly hairs. Mature stems have no wings along their sides. This trait helps tell it apart from common comfrey.

Small flowers shaped like tubes grow in curved groups. These groups have the name scorpioid cymes. Each flower grows to about half an inch long. Buds open pink, then turn blue or purple with age. The plant blooms from May through August. Chicago Botanic Garden lists blue blooms and notes that butterflies visit. The flowers and bold leaves suit woodland and wildflower plantings. The plant also suits shade, cottage, and herb gardens. Its coarse growth may look out of place in neat borders.

Grow it in soil that drains well but holds some moisture. It prefers rich, moist soil and some shade. It grows in full sun and tolerates near-full shade. Once plants take hold, they tolerate drought and grow in dry shade. Chicago Botanic Garden lists USDA zones 4–8. Cut back stems after blooms fade to help it bloom again. Trim leaves as needed to keep the plant in shape. Raise new plants from seed or pieces of root. You can also divide plants to make new ones.

Spread poses more concern than pests or disease. Missouri Botanical Garden reports no serious insect or disease problems. It also lists the plant as resistant to deer. Rhizomes and plants grown from self-sown seed can make it invasive in gardens. Small root pieces left in soil can grow again. California lists this species as a noxious weed. PFAF records the use of leaf poultices for cuts, bruises, and sprains. A poultice is a pack placed on the skin. Its notes on food use and toxicity draw on reports about another species. Those notes do not show that this plant is safe to eat.