Columbian Monkshood

Aconitum columbianum is an herbaceous perennial that grows from a large tuber-like root with a spindle shape. The stems can be from 20-300 centimeters tall and be either erect or trailing.

The leaves that are attached to the stems have as many as 7 deep divisions almost reaching the base of the leaf, but most often 3–5 divisions. There are most often about 2 millimeters of leaf tissue between the stem attachment to the leaf and the deepest point of each leaf division. The edges of each leaf segment are toothed or cleft. Each leaf is 5–15 centimeters wide.

The flowering stem can either be a single stem without branches and multiple flowers called a raceme or a branched panicle. The flowers are most often blue, but can occasionally be white, cream colored, or white with a blush of blue at the margins of the sepals. The flowers are variable in size and can measure from 18–55 mm from the top of the upright "hood" sepal to the tips of the two downward pointing sepals. The two hanging (pendulous) sepals measure 6–16 mm. …

Aconitum columbianum grows throughout the western United States, from the west coast through the Rocky Mountains. In addition, it is also found in parts of British Columbia and South Dakota. It is also reported to grow in Iowa, Wisconsin, New York, and the Mexican states of Sonora and Chihuahua. In 2016, NatureServe evaluated Aconitum columbianum as globally secure (G5). In addition it is evaluated by them as vulnerable at the state level (S3) in Wyoming.

Western monkshood is occasionally grown in gardens for its dramatic dark purple-blue blossoms. It requires a moist and rich soil as well as shade in all but the gentlest of climates.