Threatened Colorado

Endangered and Threatened Plants in Colorado

13 plants listed under the federal Endangered Species Act grow in Colorado

These plants are protected only by federal law. Colorado has no state statute protecting rare plants, and so no list of state threatened and endangered plants [1]. A 2024 law lets Colorado Parks and Wildlife study rare plants and run voluntary programs for them, but it does not give the state power to regulate their take [2].

By Threatened Colorado , Two Colorado natives , About us

Last reviewed , Checked against USFWS, CPW, CNHP sources , Sources (6)

This section profiles 13 of them: 6 endangered and 7 threatened. 10 grow nowhere else on Earth.

Showing 13 of 13 plants

Kremmling milkvetch stems hung with long, slender pods turning from green to maroon red Photo: Ellen Mayo / USFWS — Public Domain

Kremmling Milkvetch

Astragalus osterhoutii

Also: Osterhout milkvetch, Kremmling Osterhout milkvetch

USEndangered CNHP S1 Colorado only
Where:
Grand County
Blooms:
Jun–Aug
A Mancos milkvetch plant, a dense gray-green cushion of tiny leaves with a gold ring set in its center for scale, on reddish sandstone Photo: Gina Glenne / USFWS — Public Domain

Mancos Milkvetch

Astragalus humillimus

Also: Mancos milk-vetch, Mesa Verde milkvetch

USEndangered CNHP S1?
Where:
Montezuma County
Blooms:
Apr–Jun
A Ute ladies'-tresses flower spike, small white flowers spiraling up a green stem among wet meadow grasses Photo: Bekee Hotze / USFWS — Public Domain

Ute Ladies'-tresses

Spiranthes diluvialis

Also: Ute lady's tresses

USThreatened CNHP S2
Where:
Boulder, Eagle, Garfield, Jefferson, Larimer, and Moffat counties
Blooms:
Jul–Sep

Listed, but not confirmed in Colorado

USFWS lists 16 endangered or threatened plants with Colorado in their range [3]. Three of them have no confirmed Colorado record with the Colorado Natural Heritage Program: Knowlton's cactus, which CNHP says has no known occurrences in Colorado [4]; Navajo sedge; and the western prairie fringed orchid, which USFWS notes does not occur in Colorado but may be affected by water depletions in Nebraska river basins [5]. They are not profiled here.

Recently recovered

Colorado hookless cactus (Sclerocactus glaucus) was removed from the federal list on May 29, 2025, effective June 30, 2025. USFWS found that "the threats to the Colorado hookless cactus have been eliminated or reduced to the point that the species no longer meets the definition of an endangered or threatened species." The same rule notes that the listed cactus is now treated as two species, S. glaucus and S. dawsoniae [6].

Sources (6)
  1. Colorado Parks and Wildlife. “Protecting rare plants.” cpw.state.co.us (opens in a new tab)
  2. Colorado Parks and Wildlife. “Governor Polis signs invertebrates and rare plants bill, providing opportunity for CPW to manage.” May 17, 2024. cpw.state.co.us (opens in a new tab)
  3. U.S. Fish and Wildlife Service, ECOS. “Listed species believed to or known to occur in Colorado.” ecos.fws.gov (opens in a new tab)
  4. Colorado Natural Heritage Program. “Colorado Rare Plant Guide: Pediocactus knowltonii (Knowlton's cactus).” cnhp.colostate.edu (opens in a new tab)
  5. U.S. Fish and Wildlife Service. “Colorado Ecological Services Field Office: species.” fws.gov (opens in a new tab)
  6. U.S. Fish and Wildlife Service, Federal Register. “Removal of Colorado hookless cactus from the list of endangered and threatened plants (90 FR 22650).” May 29, 2025. federalregister.gov (opens in a new tab)

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