Willowherb (Epilobium ciliatum) is a highly variable clumping perennial that is part of a large complex of plants that some taxonomists separate into six or more separate species requiring technical manuals to sort things out – other botanists simply refer to all these willowherbs as E. ciliatum. To further confuse the situation, this plant is often commonly called “fireweed”, a name usually used for Epilobium angustifolium. Generally the literature agrees that E. angustifolium is more accurately called fireweed while E. ciliatum should be willowherb.
Whatever the name, willowherb is a fascinating plant. The small flowers seem to perch atop slim capsules at the stem ends. These capsules are actually inferior ovaries that become the long, narrow (up to 10 cm) pods which contain the seeds. The flowers have four notched petals that are pink, white or rose. The seed pods split in arches to expose soft tufts of hairs attached to the end of the minute brown seeds. The wind carries the seeds aloft and disperses them.
Willowherb is an upright plant that can grow only a few inches high or can soar to six feet in height. The foliage, stems and flowers are covered in hairs and glands. The opposite willowherb leaves are thickly veined, lance-shaped, and shallowly sharp toothed.
Growing in a wide variety of habitats from wetlands to moist or dry conditions, willowherb is native to North America and can be found everywhere throughout the continent except in the Deep South, Arkansas and Missouri.
The scientific name comes from the Greek. The fact that the flower surmounts the pod-like inferior ovary leads to the genus name Epilobium – “epi” meaning upon and “lobos” meaning pod. The willowherb species name means “fringed with hairs” and refers to the hairy aspect of the plant.
These willowherb plants were photographed along the shore of Eagle Lake (Lassen County CA).