Herbaceous annual that grows to be 1-3’ tall. Stems are square, swollen at leaf nodes, and covered with coarse, downward-pointing hairs intermixed with shorter glandular hairs.
OverviewOther names for this plant include:
- Common names: brittlestem hempnettle, common hemp nettle, hemp-nettle
- Scientific names: G. tetrahit var arvensis; G. tetrahit var bifida; G. tetrahit var tetrahit
- It Invades roadsides, open woods, pastures and fields. In general, hemp nettle prefers disturbed sites creating monospecific stands.
- Hemp nettle is considered an agricultural weed as well and is avoided by most grazers and also is the host for potato fungus and several nematodes.
Classification in Wisconsin: Restricted
Species Assessment Groups (SAG) were assembled to recommend a legal classification for each species considered for NR 40. The recommendation for hemp nettle was based upon this literature review developed by the department.
CAUTION: Wear long sleeves and gloves when handling. Hemp nettle exposure can irritate the skin in some people.
Leaves: Opposite, coarsely toothed and hairy on both sides. The true shape can be variable.
Flowers: Purple to pink to white flowers in dense axillary clusters. It has 5 sharp points that protrude from the flowers. Bloom from June-September.
Fruits & seeds: Each flower produces 4 nutlets each containing one seed.
Roots: Taproot with lateral roots.
Mechanical: Dig up or hand pull when in the flower bud stage. Dispose of in landfill since seeds can still mature after removed.
Chemical: Use Dicamba (230 mL/ha) mixed with MCPA (1.1 L/ha) [restricted use].
View hemp nettle pictures in our photo gallery!
ResourcesSources for content:
- Galeopsis tetrahit. In Klinkenberg, Brian. (Editor) 2012. E-Flora BC: Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver.