The plant described here is the subspecies caudata . The full species is circumboreal in distribution. Western sagewort is likely a biennial although some specimens seem to have lived more than two years. Stems are usually single from a thick taproot.
Plants can be three feet tall, but most North Dakota specimens are about two feet tall.
Basal leaves are numerous in first-year plants, but may be absent the second year. Leaf blades are divided two or three times into thread-like segments. Upper leaves are much smaller and may be undivided. Unlike many of the sages, western sagewort has no odor. Hundreds of tiny, yellowish-green flower heads form on the narrow upper half of the plant.