Masterwort is a commanding perennial herb native to the swampy stream banks and wetlands of eastern North America, where it has thrived for centuries in conditions most garden plants avoid. Also known as purple-stemmed angelica or Alexanders, this species grows 3 to 10 feet tall with distinctive dark purple or purple-blotched stems that rise dramatically above compound, deeply lobed foliage. From June through September, it produces showy clusters of tiny greenish-white to white flowers arranged in large, compound umbels up to 10 inches across. Hardy in zones 4 through 7, masterwort handles moderate water and low maintenance once established, making it a genuine workhorse for naturalized plantings and rain gardens where its tolerance for wet soil shines.
Partial Sun
Moderate
4-7
120in H x 72in W
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Low
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The dark purple stems alone make masterwort a striking architectural presence in any garden, especially when backlit by summer sun. Its ability to thrive in wet soils and swampy conditions that challenge most perennials is genuine; this is a plant born to those difficult spots near stream edges and low-lying garden areas. The showy flower umbels that bloom for months attract interest well into fall, and the plant exhibits remarkable self-sufficiency once the roots settle in, asking little beyond occasional observation.
Masterwort functions primarily as an ornamental perennial and ecological plant in designed landscapes. Its tolerance for wet soils and natural aesthetic make it especially valuable for rain gardens, wetland restorations, and naturalized plantings where it anchors the landscape with dramatic height and structure. The large, architectural foliage and extended bloom period support pollinators and other beneficial insects throughout the growing season.
No timeline data available yet for this variety.
Sow seed directly in spring or fall in medium to wet soil in full sun to partial shade. Masterwort germinates readily in optimum growing conditions.
Deadhead spent flower umbels if you wish to prevent self-seeding; otherwise, allow the plant to set seed and mature naturally. As a perennial, masterwort will die back to the ground in winter, requiring no fall cleanup beyond removing debris if desired.
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“Angelica atropurpurea inhabits the wetlands and stream banks of eastern North America, naturally distributed from Newfoundland west to Minnesota and south through the Mid-Atlantic states to Delaware and Illinois. This native perennial emerged from wild populations in precisely the boggy, seasonal flood zones where many ornamental plants simply fail, a heritage that explains its extraordinary comfort in wet soil. The common name Alexanders connects it to Old World traditions of herb cultivation, though this American species developed its character in its native wetland habitats long before gardeners recognized its ornamental and utilitarian potential.”