Hieracium piloselloides (Glaucous King-devil)
|Also known as:||Tall Hawkweed, King-devil Hawkweed|
|Habitat:||part shade, sun; open fields, roadsides, disturbed soil, high grade prairie|
|Bloom season:||June - August|
|Plant height:||12 to 40 inches|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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10 to 30 yellow dandelion-like flowers in a flat to open cluster at the tip of a long mostly naked stem. Individual flowers are about ¾ inch across, often with dark glandular hairs on the bracts and flower stalks. The compact clusters become more open as the flowers mature.
Leaves and stems:
Leaves are mostly basal in an erect rosette around the stem, 3 to 7 inches long, ¼ to ¾ inch wide, lance-elliptic tapered to a rounded point, smooth or sparsely toothed around the edges. Sometimes 1 or 2 reduced leaves are also on the lower part of the flowering stem. Leaf surfaces have a waxy bloom, the upper surface smooth or with scattered stiff hairs, the lower surface with stiff hairs along the midrib. Stems are waxy smooth at the base becoming sparsely hairy to glandular hairy near the flower cluster. Stolons (runners) are usually absent.
A relative new-comer in many parts of the state, Glaucous King-devil and other non-native weedy hawkweed species have expanded rapidly west and south the past twenty years from the Duluth area. It is not uncommon to see entire abandoned hay meadows and road ditches completely overrun. This species can be difficult to distinguish from Meadow Hawkweed (Hieracium caespitosum) which often grows side-by-side with it. Typically Glaucous King-devil is less hairy on all parts of the plant, its flower cluster less compact, and typically has no stolons. To complicate matters there is a third similar non-native hawkweed, Hieracium x floribundum, which is a hybrid between H. caespitosum and another European hawkeed, H. lactucella. It's not as widely reported but likely more prevalent than documented. Its above ground portions are very similar to H. piloselloides but the tap root is long and slender, and it also produces stolons and grows in mats. It might also be easy for the untrained eye to confuse all the hawkweeds with sow-thistles, but sow-thistles all have shiny leaves that are lobed and have spiny teeth along the leaf edges.
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Photos courtesy Peter M. Dziuk taken in Aitkin and Pine counties.
Have you seen this plant in Minnesota, or have any other comments about it?