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(Echium vulgare)



Common Names: 

Bluethistle, Viper’s Bugloss, Snake-Flower, Common Viper’s Bugloss, Bluestem, Blue Devils



Blueweed is a fairly new invader to Montana. It is a biennial or short-lived perennial that can grow between two and five feet in height.  The taproot of blueweed is black, stout and can reach depths of two feet.  During the first year, blueweed grows from a rosette, from which several stems may sprout. This rosette can be as large as one foot in diameter, but the plant does not flower in the first season. During the second season, the plant will grow and bolt quickly. Leaves are stalked, grow up to eight inches long and one inch wide at the base and then grow narrower as they travel up the stem. Leaves are hairy and have white specks that give the leaves a dimpled appearance. Stems are hairy and can be painful to touch. At the base of the hair on the stem, there will be a red or black bump on the surface which gives the stem a flecked appearance. Flowers are a distinct bright blue or purple, five lobed and funnel-shaped. They also have stiff hairs on them. Flowering occurs from June into fall and each plant can produce up to 2,000 seeds. Seeds are formed in four rough or wrinkled, gray or brown nutlets and said to resemble a snake’s head. Blueweed only reproduces by seed, and when the plant dies off, it has a distinctive appearance with tan colored, spiked, curved stalks.


Key Features:

The dimpled appearance of the leaves and bright blue to purple flowers of blueweed helps to distinguish this weed from most other weed species, as well as the stiff hairs covering all parts of the plant.



Blueweed grows in rocky pastures and rangeland, roadsides, drainage ditches, right-of-ways, fence lines, and other disturbed habitats. It thrives in sunny, arid areas and does not tolerate shade.


Currently found in the following counties:

Cascade, Flathead, Lake, Lewis & Clark, Lincoln, Madison, Mineral, Missoula, Powell, Ravalli, Sanders, Sweet Grass Treasure



  • Herbicide

  • Pulling

  • Cultivation - requires correctly time and repeated,  to be effective


Interesting Facts:

Handling blueweed is comparable to handling fiberglass; the stiff hairs are painful to touch, so be sure to wear gloves and long-sleeved shirts when handling this plant. Blueweed is toxic to livestock and to humans. According to folklore, due to the shape of the seed, it was mistakenly believed to be a cure for snakebite, thus the origin of it’s name vipers bugloss.


Commonly Confused Plants:

  • Due to its bright blue flowers and hairy foliage, blueweed is not likely to be confused with many other plants except, Paterson's curse, (Echium plantagineum)

  • Curly dock







Photo Credits: Adrian Shepherd,; Kellieann Morris; Melissa Maggio; Kellieanne Morris; Melissa Maggio

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