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Montana Field Guide

Montana Field Guides

Cascade Willow - Salix cascadensis

Species of Concern
Native Species

Global Rank: G5
State Rank: S2
(see State Rank Reason below)
State Threat Score: No Known Threats
CCVI: Extremely Vulnerable

Agency Status


External Links

State Rank Reason (see State Rank above)
Rare in Montana. Species is known in Montana only from a small area of the Anaconda-Pintlers. The remote, high-elevation habitat should greatly minimize the potential for any negative impacts to the viability of the species in the state. Accurate estimates of population levels are lacking.
General Description
Cascades Willow is a low, mat-forming shrub with prostrate stems that arise from creeping underground branches. The firm, alternate, narrowly elliptic leaves are 10-15 mm long, have short petioles, mostly inconspicuous lateral veins, and entire margins. Foliage is sparsely long-hairy when young but becomes glabrous with age. Flowers are without petals and sepals and are borne in dense spikes (aments or catkins) at the tips of lateral branches; males and females occur on separate plants. Male flowers have 2 stamens. Female aments are 1-2 cm long with dark, long-hairy scales subtending each of the 12-25 ovaries. Fruits are glabrous to long-hairy, lance-shaped capsules that are 4-5 mm long.

Flowering in July.

Diagnostic Characteristics
Salix rotundifolia and S. reticulata have elliptic leaves with more rounded tips. Salix arctica has larger female aments and leaves that are lighter beneath than above.

Species Range
Montana Range Range Descriptions


Range Comments
B.C. to WA, east to MT, WY, CO, and UT. Sparse.

Observations in Montana Natural Heritage Program Database
Number of Observations: 3

(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)

Moist cliffs, talus slopes, and tundra in the upper subalpine and alpine zones.
Predicted Suitable Habitat Model

This species has a Predicted Suitable Habitat Model available.

To learn how these Models were created see

Ecological Systems Associated with this Species

The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus vagans, Bombus bifarius, Bombus fervidus, Bombus frigidus, Bombus huntii, Bombus melanopygus, Bombus ternarius, Bombus terricola, Bombus sitkensis, Bombus occidentalis, Bombus pensylvanicus, Bombus bimaculatus, Bombus griseocollis, Bombus impatiens, and Bombus suckleyi (Plath 1934, Macior 1968, Heinrich 1976, Thorp et al. 1983, Colla and Dumesh 2010, Colla et al. 2011, Koch et al. 2012, Williams et al. 2014).

Threats or Limiting Factors
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).

  • Literature Cited AboveLegend:   View Online Publication
    • Colla, S., L. Richardson, and P. Williams. 2011. Bumble bees of the eastern United States. Washington, DC: USDA Forest Service, Pollinator Partnership. 103 p.
    • 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.
    • Koch, J., J. Strange, and P. Williams. 2012. Bumble bees of the western United States. Washington, DC: USDA Forest Service, Pollinator Partnership. 143 p.
    • Macior, L.M. 1968. Bombus (Hymenoptera, Apidae) queen foraging in relation to vernal pollination in Wisconsin. Ecology 49:20-25.
    • Plath, O.E. 1934. Bumblebees and their ways. New York, NY: Macmillan Company. 201 p.
    • Thorp, R.W., D.S. Horning, and L.L. Dunning. 1983. Bumble bees and cuckoo bumble bees of California (Hymenoptera: Apidae). Bulletin of the California Insect Survey 23:1-79.
    • Williams, P., R. Thorp, L. Richardson, and S. Colla. 2014. Bumble Bees of North America. Princeton, NJ: Princeton University Press. 208 p.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Achuff, P. L. and L. S. Roe. 1992. Botanical survey of the Goat Flat proposed Research Natural Area, Deerlodge National Forest. Unpublished report to the Deerlodge National Forest. Montana Natural Heritage Program, Helena, MT. 31 pp.
    • Argus, G. 2010. Salix. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford. Vol. 7.
    • Barge, E.G. 2015. Systematics of Lactarius in the Rocky Mountain alpine zone. M.Sc. Thesis. Bozeman, MT: Montana State University. 223 p.
    • Cripps, C.L., U. Eberhardt, N. Schutz, H.J. Beker, V.S. Evenson, and E. Horak. 2019. The genus Hebeloma in the Rocky Mountain alpine zone. MycoKeys 46: 1-54.
    • Dorn, R. D. 1970. The Willows of Montana. Montana State University Herbarium, Dept. of Botany and Microbiology, Bozeman, Montana. 18 pp.
    • Dorn, R.D. 2010. The genus Salix in North America north of Mexico. 59 pp.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
    • Vanderhorst, J.P. 1994. Sensitive plant surveys in the Gallatin National Forest, Montana. Unpublished report to the Gallatin National Forest. Montana Natural Heritage Program, Helena, MT. 54 pp.
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Citation for data on this website:
Cascade Willow — Salix cascadensis.  Montana Field Guide.  .  Retrieved on , from