Flower profile
Columbian monkshood
Aconitum columbianum
Columbian monkshood (Aconitum columbianum) is a flowering plant in the Ranunculaceae family, native in the lower 48 states, blooming mostly July–August across the U.S.
Columbian monkshood is a wildflower that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 3 states, and across the U.S. it's most often seen in bloom in July–August.
*iNaturalist research-grade observations, as of October 17, 2026.
Quick look
Aconitum columbianum is a species of flowering plant in the buttercup family known by the common names Columbian monkshood or western monkshood.
- It belongs to the Ranunculaceae family. iNaturalist
- USDA PLANTS describes it as an herb (forb) with a perennial life cycle. USDA PLANTS
- USDA PLANTS lists it as native in the lower 48 states and records it in 13 states. USDA PLANTS
- NatureServe lists it as native to Colorado, Wyoming and Idaho. NatureServe
- In Colorado, most iNaturalist sightings of it in flower come in July–August. iNaturalist
- USDA PLANTS lists its flower color as blue. USDA PLANTS
- USDA PLANTS gives its bloom period as early summer. USDA PLANTS
- USDA PLANTS lists a mature height of about 5 ft. USDA PLANTS
- iNaturalist has 2,232 research-grade sightings of it in Colorado, ranking #70 among the 160 flowers on our Colorado list. iNaturalist
- iNaturalist has 732 research-grade sightings of it in Wyoming, ranking #27 among the 113 flowers on our Wyoming list. iNaturalist
- iNaturalist has 489 research-grade sightings of it in Idaho, ranking #73 among the 143 flowers on our Idaho list. iNaturalist
When does it bloom?
Conservation status
- Federal (U.S. ESA)
- Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. USFWS ECOS
- NatureServe global
- G5 Secure worldwide. NatureServe
- Colorado
- No list Colorado has no state law listing endangered or threatened plants, so we show NatureServe's Colorado ranks instead. NatureServe: S4, apparently secure in Colorado.
- Wyoming
- No list Wyoming has no state law listing endangered or threatened plants, so we show NatureServe's Wyoming ranks instead. NatureServe: S4, apparently secure in Wyoming.
- Idaho
- No list Idaho has no state law listing endangered or threatened plants, so we show NatureServe's Idaho ranks instead. NatureServe: SNR, not yet ranked in Idaho.
- Rare elsewhere
- No other U.S. state ranks it S1, S2, SH or SX.
Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.
Can you eat it?
USDA PLANTS rates its toxicity as “moderate.” (USDA's rating covers people and livestock and doesn't say which parts.) NC State Extension has no page for it. USDA PLANTS
It isn't on the ASPCA plant list.
🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.
Where does it grow?
USDA PLANTS records columbian monkshood in 13 states.
recorded by USDA PLANTS on our state lists not recorded
See the full list of states
Arizona, California, Colorado, Idaho, Iowa, Montana, Nevada, New Mexico, Oregon, South Dakota, Utah, Washington, Wyoming.
Colorado counties with USDA records: Alamosa, Boulder, Chaffee, Conejos, Costilla, Custer, Dolores, El Paso, Garfield, Gilpin, Grand, Gunnison, Hinsdale, Huerfano, Jackson, La Plata, Lake, Larimer, Las Animas, Mineral, Montezuma, Ouray, Park, Rio Blanco, Rio Grande, Routt, Saguache, San Juan, Teller.
Wyoming counties with USDA records: Albany, Big Horn, Carbon, Crook, Fremont, Johnson, Laramie, Natrona, Niobrara, Park, Platte, Teton, Uinta, Weston.
Idaho counties with USDA records: Ada, Adams, Bannock, Blaine, Boise, Bonner, Cassia, Clearwater, Custer, Elmore, Franklin, Fremont, Gem, Idaho, Kootenai, Latah, Lemhi, Nez Perce, Owyhee, Shoshone, Twin Falls, Valley.
Growing conditions
USDA PLANTS gives Columbian monkshood a medium shade tolerance, low drought tolerance and high moisture use. It is rated for soil pH 5.4 to 7.2 and winter lows down to -28 °F.
- Shade tolerance
- Medium
- Drought tolerance
- Low
- Moisture use
- High
- Soil textures it is adapted to
- coarse, medium, fine
- Soil pH range
- 5.4 to 7.2
- Minimum temperature tolerated
- -28 °F
- Frost-free days needed (minimum)
- 110
- Annual precipitation range
- 12 to 50 inches
- Minimum root depth
- 10 inches
- Salinity tolerance
- None
- Fertility requirement
- Medium
- Growth rate
- Moderate
- Lifespan
- Moderate
- Active growth period
- Spring and Summer
- Fruit or seed
- Black · Summer to Summer
- Can be propagated by
- container, seed
- Commercial availability
- Routinely Available
From the USDA PLANTS characteristics data for ACCO4. USDA ratings are general guidance for the species, not a guarantee for your garden.
Names, range and relatives
Native status by region (USDA PLANTS): Canada: Native; Lower 48 states: Native.
County records: USDA PLANTS lists it in 192 counties across 12 states; the most are in Colorado (29), Utah (28), California (26).
Other Aconitum on Bloomipedia (1): Larkspurleaf monkshood.
More from the Ranunculaceae family (48 on Bloomipedia; most observed first): Lesser celandine, Rue anemone, Red columbine, Wood anemone, Western columbine, Marsh marigold, White baneberry, Round-lobed hepatica.
More Colorado flowers
Sources
- USDA, NRCS. PLANTS Database, profile ACCO4.
- iNaturalist, Aconitum columbianum: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
- Wikipedia, Aconitum columbianum (lead quoted under CC BY-SA 4.0).
- Colorado: Colorado noxious weed lists A, B and C (8 CCR 1206-2, eff. May 15, 2025).
- Wyoming: Wyoming state designated noxious weeds (W.S. 11-5-102(a)(xi)), as listed by the Wyoming Weed & Pest Council.
- Idaho: Idaho noxious weeds (IDAPA 02.06.09, Section 220).
- USFWS, ECOS species database (ESA listing check), October 17, 2026.
- NatureServe Explorer, Aconitum columbianum (global and state ranks).
- Edibility and toxicity: USDA PLANTS.
- Photo: Loren Cassin Sackett via iNaturalist · CC BY 4.0 · resized.