Culture
Best grown in organically rich, medium to wet but well-drained soils in part shade. May tolerate full sun only in temperate climates with consistently moist soils. Soils must be kept uniformly moist and not allowed to dry out. Best performance occurs in cool summer climates where night temperatures consistently dip below 70F degrees, which unfortunately is a cultural preference that does not fit the profile of a typical St. Louis summer where this plant often labors. In optimum growing conditions, plants will spread by stolons and/or self-seeding in a non-invasive manner to form colonies. Deadhead flowerheads after bloom if self-seeding is unwanted (deadheading may also prolong bloom).
Noteworthy Characteristics
Astrantia major, commonly called greater masterwort, is an upright, umbelliferous, stoloniferous, herbaceous perennial (carrot family) that is native to mountain meadows, grasslands, woodland clearings and moist areas near streams in Europe and western Asia. Each flowerhead (2-3" diameter) features dense, compact, domed umbels of tiny greenish-white flowers which form a delicate pincushion-like center subtended by a showy collar of papery, petal-like, creamy white involucral bracts. Flowers bloom late spring to early summer atop wiry, branched, nearly leafless stems rising to 24" tall above an 18" tall basal clump of deeply divided deep green leaves (3-6" long) which are palmately cut into 3 to 7 (usually 5) toothed lobes.
Genus name comes from a Greek word astron meaning star in reference to the flower head shape or from magistrantia (derived from the Latin word magister meaning master or teacher).
Specific epithet means bigger or larger.
‘Claret’ is a great masterwort cultivar that is noted for its dark red flowers and nearly black stems. This is an umbelliferous, stoloniferous, clump-forming perennial that typically grows to 24” tall. Each flower is a domed umbel of red florets subtended by a ruff of papery, petal-like, dark wine red involucral bracts. Flowers bloom from late spring to early summer. Bracts usually remain attractive after bloom. Medium green leaves, with each leaf being palmately cut into 3-7 (usually 5) toothed lobes. Leaves appear primarily in basal clumps, with smaller versions on the stems.
Problems
No serious insect or disease problems. Slugs are occasional visitors.
Uses
Part shade areas of perennial borders. Also effective in open woodland, wild or cottage gardens. Good perennial for sun-dappled areas below open trees. Often thrives along moist stream banks (above water level). Plants will spread to fill in open spaces in woodland gardens, but are not considered invasive. May form colonies over time. Excellent for dried flower arrangements.