Polymnia canadensis

Species Native to Missouri
Common Name: small-flowered leaf cup
Type: Herbaceous perennial
Family: Asteraceae
Native Range: North America
Zone: 4 to 7
Height: 2.00 to 4.00 feet
Spread: 2.00 to 3.00 feet
Bloom Time: July to October
Bloom Description: White with yellowish center (rays sometimes absent)
Sun: Part shade
Water: Medium
Maintenance: Low
Flower: Showy
Leaf: Fragrant

Culture

This is a woodland species that performs best in part shade or dappled sun locations. Avoid full sun. It prefers a rocky, limestone soil that receives consistent moisture but is well-drained. Appreciates a leaf-mold mulch. May self-seed in optimum growing conditions.

Noteworthy Characteristics

Polymnia canadensis, commonly called small-flowered leaf cup, whiteflower leaf cup or Canadian leaf cup, is a rough-hairy branching perennial that is native primarily to woodland areas with calcareous soils from New England, southern Canada and Minnesota south to Georgia and Oklahoma. In Missouri, it is typically found on limestone talus and bluff ledges and in rocky wooded limestone slopes primarily in the Ozark region (Steyermark). It grows in a clump to 2-4’ tall on yellowish-green hairy stems (sometimes spotted purple) clad with pinnately 3- to 5-lobed green leaves (4-10” long). Upper stem leaves have fewer lobes. Leaves are aromatic when crushed. Small, aster-like flowers (1/ 2” diameter) with white rays and yellowish center disks bloom July to October in terminal cymes. Rays are somewhat inconspicuous and are often few or absent. Steyermark recognized P. canadensis f. radiata as a form in which the rays were minute or absent. Large flowered leaf cup (Smallanthus uvedalius) is a similar plant with, as the common name suggests, larger flowers with prominent rays.

Specific epithet means of Canada.

Problems

No known serious insect or disease problems.

Garden Uses

Best in native plant areas or woodland gardens.