Inula helenium (Elecampane)
|Also known as:||Horse Yellowhead|
|Habitat:||part shade, sun; disturbed soil; roadsides, fields, open woods, clearings|
|Bloom season:||July - September|
|Plant height:||2 to 8 feet|
|Wetland Indicator Status:||GP: none MW: FACU NCNE: FACU|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Flowers are at the end of branching stems at the top of the plant and arising from leaf axils in the upper plant. Individual flowers are 2 to 4 inches across with 50 to 100 very narrow ray flowers (petals). The central disk is dome-shaped and covered in hundreds of tiny yellow flowers that turn brown with age, maturing in rings giving the disk something of a bull's-eye appearance.
The leaf-like bracts surrounding the base of a flower are in several layers, the outer largest, ½ to ¾ inch long, lance-oblong to egg-shaped with a softly pointed tip, velvety hairy on the underside, the inner bracts becoming smaller, less hairy, and more scale-like. Flower stalks are finely hairy.
Leaves and stems:
Leaves are basal and alternate, velvety hairy on the underside and more rough-hairy on the upper surface, serrated and wavy around the edges, and have a prominent white midvein. Basal and lower leaves are 6 to 16 inches long and 4 to 8 inches wide, lance-elliptic and long stalked, becoming smaller, stalkless, clasping and more lance-oblong on the upper stem. Stems are erect, unbranched except in the flowers, green to purplish, and short-hairy.
The center disk forms a head of dry seed each with a tuft of fine bristles at the top.
Elecampane has been noted for its herbal uses since ancient Greek and Roman times, and is widely available in the nursery trade. Native to parts of Europe and western Asia, it has escaped cultivation but is not currently very widespread in Minnesota. However, reports from an Early Detection weed group in MN have recorded several populations near I-35 around Pine City, so it appears to be on the move. It is noted as invasive in Oregon and potentially invasive in Wisconsin. It may be wise to nip this one before it has a chance to become really established here. Prior to flowering it may be mistaken for a Silphium species, but as Elecampane develops it is easily identified by its narrow rays on the flowers, large leaf-like floral bracts, velvety hairy leaves, clasping stem leaves and large basal leaves that are typically wavy around the edges.
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Photos courtesy Peter M. Dziuk taken in Kanabec County.
Have you seen this plant in Minnesota, or have any other comments about it?