With millions of acres of land maintained in its boreal state, Minnesota is home to many rare plants. Unfortunately, many of these plants are now classified as "threatened" as their habitats become lost due to changes in land use or deforestation.
Nodding Wild Onion (Allium cernuum)
Allium cernuum is a perennial herb with a strong onion odor. It grows on north or northwesting facing slopes on cliff edges, stream bottomlands or above waterways. It grows in white pine forests or hardwood forests alongside moss, wild ginger and bulblet ferns. Prefers partial shade. Appears early in spring with white umbel flowers opening in late June. Seeds ripen in late July through early September. Considered a threatened species in Minnesota.
Eastern Hemlock (Tsuga canadensis)
With a estimated population of a mere 50 trees in the entire state, the eastern hemlock is currently under consideration for elevation to endangered status. It grows to heights of 100 feet or more with horizontal drooping branches and evergreen leaves. It has a growth habit similar to other conifers but the topmost part of the central leader has a drooping habit. It grows in mixed forests of conifers and hardwoods containing yellow birch, northern white cedar and white pine in moist soils in sheltered locations. Minnesota is at the furthest northwestern edge of its natural growing range. Logging and damage from the white tailed deer have contributed to the decline of populations of the eastern hemlock in Minnesota.
Ram's-Head Lady's Slipper (Cypripedium arietinum)
Once growing throughout the northern forests of Minnesota, recent surveys have shown that it is not growing in the wild south of Aitken County, which is located in the northern third of the state. Removal of native jack pine forests may compromise the ram's head lady's slipper and it was classified as a threatened species in 1996. Ram's head lady's slipper grows in coniferous forests, swamps, bogs or lowland forests of northern white cedar, tamarak or balsam fir. Removal of mature trees in these habitats may contribute to its decline, due to the increased sunlight from the loss of the upper leaf canopy in the forest. It flowers in late May through the middle of June. Plants dug from the wild do not survive transplanting into cultivation.