Artemisia absinthium / wormwood

Adjectives: disturbed, fragrant, non-native, ruderal, silvery leaves, weed

Also known as: absinthe, artemisia, absinth sage, absinth wormwood, absinth sagewort, common sagewort, absinthe mugwort, absinthium, Romanian wormwood

---

Wormwood is an herbaceous perennial growing from a thick taproot, up to 2 inches in diameter. The stems are straight and up to 4 feet tall and a single plant may have 20 or more. They are grooved, branched and silvery white due to their extensive covering of silver-white trichomes (hairs).  Wormwood is grown as an ornamental plant and is used as an ingredient in the spirit absinthe and some other alcoholic beverages. It has been extensively studied for its medicinal properties, including as a source of anti-cancer drugs.

As it is the leaves that are most visible and useful for identification, we’ll start there. Wormwood leaves are also hirsute, but less so on the upper surface. Thus, they are greenish-grey above and white below. The trichomes have oil-producing glands, largely responsible for their sage aroma. Basal leaves may be as long as 10 inches, and 2 or 3 times compound, with long petioles. Typically, these have withered away prior to flowering time. Stem leaves are smaller (only up to about 4 inches) and less divided. At the very top of the stems, leaves can be both simple (undivided) and sessile.

Wormwood flowers are pale yellow, tubular, and clustered in spherical, drooping heads. Flower stalks also have dense, silky hairs. The heads are clustered in leafy and branched panicles. Individual flowers are small, ¼-inch, with no petals, facilitating wind pollination (and allergen distribution). If you look closely, you’ll see that each clump actually has dozens of disk florets in the center. Flowering occurs from early summer to early autumn. The seeds are small, and simply fall from the plants when mature.

Wormwood grows primarily on disturbed sites within grasslands, pastures, perennial crops, and on land abandoned from cultivation. It may form extensive stands although perhaps not in the Valley. Because of its requirement to re-grow each year, it is not a very good invader of established systems.