Cinnamon willowherb's riot of delicate foliage and diminutive flowers that bloom in late summer add charm to wetter areas of the landscape. This native of the northeastern and midwestern US (another common name is eastern willowherb) is a pioneer plant that thrives on fire and other soil disturbances. It grows up to 3 feet tall in a wide range of moist to wet soils. It flowers best in full sun but tolerates light shade, making it an ideal wildflower for poorly drained areas that receive good sun exposure.
Cinnamon-colored tufts of hair on the tiny seeds of this plant are responsible for the common name. Occasional purple veining or spots on the leaves provide another common name, purpleleaf willowherb. The scientific name translates as "colored flower upon a pod" in Greek. A better description follows: "Tiny, pink to white flowers appear to be perched atop a long stem, except that the long tube-like stems are actually their ovaries where seeds will develop! This unusual configuration is the main characteristic of willowherbs." (Susan Sprout, Northcentral Pennsylvania Conservancy, 2023). The leaves sometimes have purple veining or spots, giving rise to the common name "purple-leaved willowherb." The stems are often a reddish purple that complements the pinkish flowers and purple-tinged leaves. In the fall and winter, the stems and burst calyxes change to tan and form a bushy tangle at the top of the plant.
Native habitats include poorly-drained prairies; moist, wooded areas; wetland margins; bogs; marshes; and edges of rivers and ponds. Use in woodlands, edges of water features, rain gardens, and marshy areas.
Plant Characteristics:
Grows 1-3' tall.
Prefers full sun to light shade.
Prefers moist to wet conditions and adapts to a variety of soils, including clay and sandy. Tolerates occasional flooding.
Flowers bloom July-September. Single flowers with long calyx tubes on short stalks (peduncles) grow from upper axils of leaves. The erect, softly hairy calyx tube terminates in 4 lanceolate sepals that are often tinted purple or pink. The sepals are a little shorter than the petals. The 4 notched petals are white or light pink and about 1/3" wide. The prominent pistil is often knobby at the end and surrounded by several stamens.The calyx tube matures into an elongated seed capsule that splits to release a tiny seeds with small tufts of reddish-brown hair for wind dispersal.
Hairless leaves are opposite or alternate, sessile or with short petioles, and up to 4" long. They are narrowly lanceolate in shape with serrated margins.
Stems are square or round with downy hair that disappears as the stem ages. The root system is fibrous and produces rhizomes, which enables this plant to spread vegetatively.
Reproductive system: hermaphroditic (perfect flower has male and female parts).
Wildlife Value:
Host plant for 20 species of Lepidoptera larvae, including the moths white-lined sphinx, pearly wood nymph, Scythris magnabella, and many-lined carpet (one of 5 specialist moths). The flowers attract bees and flower flies, which seek nectar and pollen. The foliage is non toxic and occasionally browsed by mammals, but it has low food value.
Medicinal, Edible, and Other Uses:
No known medical uses.
Resuorces:
North Central Pennsylvania Conservancy: https://npcweb.org/underfoot-purpleleaf-willowherb/
Illinois Wildflowers: https://www.illinoiswildflowers.info/wetland/plants/cn_willowherb.htm
Minnesota Wildflowers: https://www.minnesotawildflowers.info/flower/purple-leaf-willowherb
Plants for a Future: https://pfaf.org/user/Plant.aspx?LatinName=Epilobium+coloratum
Friends of the Wild Flower Garden: https://www.friendsofeloisebutler.org/pages/seasonal/fiveedgeplants.html