Asteraceae : Arnica cordifolia
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Family Name
Asteraceae
Common Name
Heartleaf arnica
Description
Arnica cordifolia is a perennial herb arising from long, creeping rhizomes, growing to 60 cm tall. It has two to four sets of opposite leaves on the flowering stem, each having a long petiole. Basal leaves are cordate, with long petioles and dentate margins. The cauline leaves are heart-shaped to arrowhead-shaped, with finely dentate margins. Leaf blades are 4-12 cm long and 2-9 cm wide. The inflorescence is composed of a single or occasionally 2-3 turbinate to campanulate heads, each 5–9 cm wide. The involucral bracts are 1-2 cm long, covered with white-hairs and sometimes studded with resin glands. Each head has 10-15 ray flowers with ligules 15-30 mm long and the center of each head contains several golden yellow disc florets. The achenes are 6-9 mm long with short hairs and/or glands. The pappus has long white barbed hairs. The flowers usually bloom from May through August. Heartleaf arnica grows in western South Dakota.
Horticulture Notes
Seed collection: Seeds mature in late summer and into the fall. Collect the achenes when they begin to be released from the heads.
Germination: Seeds need a 60-day cold treatment to break dormancy. Planting seeds out in the fall fulfills this requirement.
Vegetative propagation: Sections of rhizomes can be transplanted in spring.
Soils: Will grow in a wide range of loamy to sandy and rocky soils.
Light: They grow best in partial shade.
Water: Can tolerate dry soils but grow best in moist sites that are well-watered.
Additional Notes
Heartleaf arnica is an attractive addition to any native plant garden. It produces numerous yellow flowers and spreads by rhizomes. It is resistant to deer and attracts native bumblebees and butterflies.