Search Field Guide
Advanced Search
MT Gov Logo
Montana Field Guide

Montana Field Guides

Bushy Knotweed - Polygonum ramosissimum
Other Names:  [including] Polygonum leptocarpum

Native Species

Global Rank: G5
State Rank: SU
C-value: 3

Agency Status


External Links

General Description
Stems erect, branched, 8–70 cm high. Leaves short-petiolate, often moldy beneath, linear to narrowly lanceolate, 1–3 cm long,; stipules 5–14 mm long, lacerate, brownish. Flowers 2–4 mm long, 1 to 3 in leaf axils; pedicels 1–6 mm long, erect; tepals green with yellow or white to pink margins. Achene dark brown, 3-sided (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Our plants are subspecies ramosissimum. The Great Plains Flora includes P. leptocarpum in its treatment.

Species Range
Montana Range Range Descriptions


Range Comments
Throughout North America (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX). Native to eastern North America, but possibly introduced west of the Continental Divide (Lesica 2012).

Observations in Montana Natural Heritage Program Database
Number of Observations: 112

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Grasslands, roadsides, ephemeral wetlands; plains, valleys (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus bifarius, Bombus flavifrons, Bombus frigidus, Bombus melanopygus, Bombus sylvicola, Bombus occidentalis, Bombus pensylvanicus, Bombus insularis, and Bombus kirbiellus (Macior 1974, Colla and Dumesh 2010).

  • Literature Cited AboveLegend:   View Online Publication
    • Colla, S.R. and S. Dumesh. 2010. The bumble bees of southern Ontario: notes on natural history and distribution. Journal of the Entomological Society of Ontario 141:39-68.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Macior, L.M. 1974. Pollination ecology of the Front Range of the Colorado Rocky Mountains. Melanderia 15: 1-59.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Jones, W. W. 1901. Preliminary flora of Gallatin County. M.S. Thesis. Bozeman, MT: Montana State College. 78 pp.
    • Meier, G.A. 1997. The colonization of Montana roadsides by native and exotic plants. M.Sc. Thesis. Bozeman, MT: Montana State University. 45 p.
    • Seipel, T.F. 2006. Plant species diversity in the sagebrush steppe of Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 87 p.
  • Web Search Engines for Articles on "Bushy Knotweed"
Login Logout
Citation for data on this website:
Bushy Knotweed — Polygonum ramosissimum.  Montana Field Guide.  .  Retrieved on , from