Astrantia major aka Astrantia

Astrantia major, or greater masterwort, belongs to the carrot family, Apiaceae. This herbaceous perennial comes from central and southern Europe to the northern Caucasus. It grows in mountain meadows, grasslands, and woodland gaps. It also lives in damp ground beside streams. It is not native to Britain or Ireland. Its leaves die back for winter.

The plant forms an upright clump and spreads through stolons. Garden plants reach about 1.6–3.3 feet [0.5–1 metre] tall. They can spread to about 1.6 feet [0.5 metre] wide. Deep green leaves form a mound beneath the flower stems. Each leaf has three to five lobes. The slender stems branch and carry few leaves. The plant may take two to five years to mature.

Flowers appear from May to July, above the leafy clump. Small greenish-white flowers gather in rounded umbels. Each head measures about 0.17–0.25 feet [0.05–0.08 metre] across. A ring of thin, papery bracts surrounds each cluster. These look like petals but are not petals. They are white or cream, with green and pink tints. Clear veins mark the bracts. The heads suit both fresh bouquets and dried flower work.

Give this plant fertile soil with plenty of organic matter. It grows in loam or clay across acid to alkaline soils. Partial shade suits it well, including light shade beneath trees. Full sun works best in cool climates with steady soil moisture. Keep the soil moist, but allow excess water to drain. RHS notes some tolerance of drier conditions. Missouri Botanical Garden warns against letting the soil dry out. Cool summers suit it better than hot nights. It is hardy in USDA zones 4–7 and carries RHS rating H7.

Use it in shaded borders, cottage gardens, or open woodland gardens. It also suits moist stream banks above the water line. Stolons and self-sown seedlings can build colonies without invasive spread. Remove spent heads to limit seedlings and perhaps extend flowering. Cutting back after bloom tidies plants and prompts fresh leaves. Divide clumps in spring, or sow ripe seed in a cold frame. Slugs, aphids, and astrantia leaf miners may attack it. Powdery mildew can occur, though serious problems are not usual. Plants For A Future lists no known food uses or hazards. It records root preparations as purgatives and whole-plant infusions as mild diuretics. Those reported uses do not establish safety for home treatment.