Pacific Blackberry - Rubus ursinus
* (see State Rank Reason below)
MNPS Threat Rank
State Rank Reason (see State Rank above)
Rubus ursinus occurs on the edge of its range in northwesterm Montana. Where habitat is appropriate, the species is present. Many populations appear stable and appear tolerant to some manmade disturbances.
- Details on Status Ranking and Review
ScoreB - 100-250 sq km (~40-100 sq mi)
Area of Occupancy
ScoreD - 6-25 4-km2 grid cells
Number of Populations
ScoreB - 6 - 20
Number of Occurrences or Percent Area with Good Viability / Ecological Integrity
ScoreC - Few (4-12) occurrences with excellent or good viability or ecological integrity
ScoreD - Broad. Generalist or community with all key requirements common
ScoreU - Unknown
ScoreU - Unknown
ScoreU - Unknown
CommentNo known threats.
ScoreC - Not intrinsically vulnerable
Plants: Shrub with trailing stems bearing leaves the first year (primocanes), flowering the second (floricanes) (Hitchcock et al. 1961).
Stems: The trailing primocanes up to 5-6 m in length, slender, at first pubescent, eventually glabrate, rooting frequently at the ends (Hitchcock et al. 1961), often with a powdery white bloom, armed with retrorse or erect prickles 4-10 mm in length; floral branches to 20 cm in length (FNA 2015), erect, leafy (Lesica 2012).
Leaves: Glabrate with 3 leaflets (Lesica 2012), occasionally pinnately compound or simple; leaflets ovate or narrowly so, 3.5-12 cm in length, 3-10 cm in width (FNA 2015), with doubly serrate-dentate margins (Hitchcock et al. 1961), the terminal leaflet lobed and larger than the lateral two (Lesica 2012); the lower surface bearing straight prickles on the larger nerves; stipules 7-17 mm in length, linear or thread-like (FNA 2015).(Lesica’s contribution adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)
Flowering usually April-early August (Hitchcock et al. 1961) but as early as January and late as September (FNA 2015).
BC s to CA, ID and MT; Mexico (Baja California) (FNA 2015).
Observations in Montana Natural Heritage Program Database
Number of Observations:
(Click on the following maps and charts to see full sized version)
Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
Shrublands, disturbed places (FNA 2015), often on forest lands following burning or logging, prairies (Hitchcock et al. 1961), wet forests, often along roads, streams; valleys (Lesica 2012).(Lesica’s contribution from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)
Flowers: Flowers unisexual, in few-flowered cymes (terminal flowers opening first); calyx with long soft hairs, purple, stipitate-glandular; sepals narrowly lanceolate, 5–8 mm in length; petals white, 10–16 mm in length on staminate flowers; pistillate flowers with abortive anthers and oval petals 6–10 mm in length (Lesica 2012); ovaries smooth to hairy (FNA 2015).
Fruit: Fruit a cylindrical, red blackberry 2–3 cm in length (Lesica 2012) with 20-50 drupelets (FNA 2015).
Diocious (Hitchcock et al. 1961).(Lesica’s contribution adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)
Can be difficult to remove from gardens (Hitchcock et al. 1961).
Fruit of the Pacific Blackberry is delectable, such that it is a progenitor of horticultural varieties, including Mammoth Berry, Loganberry, and Boysenberry (Hitchcock et al. 1961).
- Literature Cited AboveLegend: View Online Publication
- Flora of North America Editorial Committee, eds. 2015. Flora of North America North of Mexico. Volume 9. Magnoliophyta: Picramniaceae to Rosaceae. New York, NY: Oxford University Press, Inc. 752 pp.
- Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson. 1961. Vascular Plants of the Pacific Northwest, Part 3. Saxifragaceae to Ericaceae. Seattle, WA and London, England: University of Washington. 614 pp.
- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.