,
Common Name: masterwort
Type: Herbaceous perennial
Family: Apiaceae
Zone: 5 to 7
Height: 2 to 2.5 feet
Spread: 1 to 1.5 feet
Bloom Time: May to July
Bloom Color: White
Bloom Description: White
Sun: Part shade
Water: Medium to wet
Maintenance: Medium
Flowers: Showy Flowers
Tolerates: Wet Soil
Uses: Will Naturalize
Culture
Best grown in organically rich, medium to wet, well-drained soils in part shade. 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 70 degrees F… a cultural preference that unfortunately does not fit the profile of a typical St. Louis area summer where the plant often labors. In optimum growing conditions, plants may spread to form large clumps by both stolons and self-seeding.
Noteworthy Characteristics
‘Snow Star’ is an umbelliferous, stoloniferous, clump-forming masterwort cultivar that typically grows 24-30” tall and features domed umbels of white florets subtended by a showy ruff of papery, petal-like, white involucral bracts tipped with green. Long late spring to early summer bloom. Bracts usually remain attractive well after bloom. Medium green leaves are palmately cut into 3-7 (usually 5) toothed lobes. Leaves appear primarily in basal clumps, with smaller versions on the stems. ‘Snow Star’ is often sold as a cultivar of Astrantia major.
Problems
No serious insect or disease problems. Slugs are occasional visitors.
Garden Uses
Perennial borders. Naturalize in open woodland, wild or cottage gardens.