Artemisia annua

This introduced plant is a summer annual about 3-6' tall; it is more or less erect and branches regularly. The light green stems are angular-terete, ridged, and hairless; the secondary stems are ascending or spreading. The alternate leaves are up to 6" long and 4" across, becoming smaller as they ascend the stems. They are green and hairless. Each leaf is pinnately divided (double or triple) into slender lobes that are narrowly lanceolate or oblong-lanceolate; some of these lobes are cleft or toothed along their margins. The lower leaves have petioles, while the upper leaves are sessile. The upper stems terminate in floral panicles up to 1½' long and half as much across. The panicles are abundantly branched, each branch consisting of a raceme of small drooping flowerheads. about 1-2 mm. across (1/8" or less). Each flowerhead is about 2 mm. across (1/8" or less); it has many tiny disk florets. At the base of each flowerhead, there are 6 oblong bracts that are dark green. The blooming period occurs from late summer into the fall. There is no floral scent, although the foliage has a sweet fruity fragrance. Pollination is by wind. Upon maturity, each floret is replaced by a single achene. These achenes are small enough to be carried aloft by the wind, even though they lack tufts of hair. The root system consists of a branching taproot. This plant reproduces by reseeding itself.

Another common name for this plant is 'Sweet Annie.' Annual Wormwood is a non-woody summer annual that has hairless foliage with a sweet fruity fragrance. Other Artemisia spp. (Wormwoods) are often herbaceous biennials or woody perennials with hairy foliage (at least on the underside of their leaves). Many of these species have foliage with a smoky fragrance that resembles the seasoning 'Sage.' Annual Wormwood differs from a similar species, Artemisia biennis (Biennial Wormwood), by its double or triple pinnate leaves and spreading floral panicles. The latter species has simple pinnate leaves and a more spike-like inflorescence. The foliage of Annual Wormwood contains a chemical that is useful in the treatment of malaria.

Annual Wormwood is occasional throughout Illinois (see Distribution Map). It was introduced from Eurasia as a medicinal herb. Escaped plants usually don't persist in a given location. Habitats include woodland borders, low-lying areas along rivers and ponds, fields, vacant lots, edges of yards, fence rows, gardens, back alleys in older cities, and areas along railroads and roadsides. Disturbed habitats are preferred. Annual Wormwood is still cultivated occasionally in gardens. Faunal Associations

Artemisia annua L.:
Canada (North America)
Ecuador (South America)
Peru (South America)
United States (North America)
China (Asia)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Canada

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

Distribution: Central & South Europe, Turkey, S. Russia, Palestine, Syria, Iran, Afghanistan, Pakistan, India and South China; introduced and naturalised in Canada and U. S. A.

Annuals, 30–200(–300) cm, sweetly aromatic. Stems mostly 1, erect, green, turning to reddish brown with age, simple (smooth or ribbed), glabrous or sparsely hairy. Leaves cauline, bright green; blades triangular to broadly ovate, 2–5(–10) × 2–4 cm, 2–3-pinnatifid (lobes relatively narrow, ± toothed), faces glabrous, gland-dotted. Heads (nodding, peduncles 2–5 mm) in open, (diffusely branched, leafy) arrays 15–30(–40) × 10–20 cm. Involucres globose, 1.5–2.5 × 1.5–2.5 mm. Phyllaries (green) lanceolate, glabrous. Florets: pistillate (0–)10–20; bisexual 18–24; corollas pale yellow (broadly campanulate), 0.5–1 mm, glabrous. Cypselae oblong (flattened), 0.3–0.8 mm, glabrous. 2n = 18.

Erect, annual herb with up to 1.5 m tall, sparsely puberulous, striate, red-tinged, simple stem. Basal and lower stem leaves long petiolate, ovate, 3-pinnatisect, 3 – 10 x 2 – 5 cm, primary segments remote, oblong,, pinnatisect or pinnatipartite, secondary segments pinnatifid into lanceolate, 1 – 5 x 0.5 – 1 mm, acute, entire or toothed lobules; upper and mid stem leaves subsessile or sessile, (1-) bipinnatisect, basally auriculate, uppermost in floral region lanceolate, dentate or linear and entire. Capitula heterogamous, pedunculate, numerous, hemispherical, remote, 1.5 – 2 x 2 – 3 mm, nodding in lax, 10 – 50 x 5 – 20 cm, terminal panicle with oblique or patent branches. Involucre 3-seriate, phyllaries glabrous, shining; outermost linear-oblong, green with narrow scarious margins, inner oblong-ovate or broadly ovate-elliptic, with broad scarious margins. Receptacle conical, glabrous. Florets up 30, greenish-yellow, all fertile; marginal florets 5-10, with irregularly 2-toothed, filiform, glandulose corolla tube; disc-florets 5-20, bisexual, with broadly tubular, 5-dentate, c. 1 mm long corolla. Cypselas narrowly oblanceolate, 0.6 – 0.8 mm long, brown.

A.wadei Edgew. in Trans. Linn. Soc. 20: 72. 1846; A. stewartii C.B.Clarke, Comp. Ind. 163. 1876.

Artemisia chamomilla C. Winkler

Annual Wormwood is occasional throughout Illinois (see Distribution Map). It was introduced from Eurasia as a medicinal herb. Escaped plants usually don't persist in a given location. Habitats include woodland borders, low-lying areas along rivers and ponds, fields, vacant lots, edges of yards, fence rows, gardens, back alleys in older cities, and areas along railroads and roadsides. Disturbed habitats are preferred. Annual Wormwood is still cultivated occasionally in gardens. Faunal Associations

Fl. Per.: August-September.

The following is a representative barcode sequence, the centroid of all available sequences for this species.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 3
Specimens with Barcodes: 6
Species With Barcodes: 1

Rounded Global Status Rank: GNR - Not Yet Ranked

Canada

Rounded National Status Rank: NNA - Not Applicable

United States

Rounded National Status Rank: NNA - Not Applicable

These species are introduced in Switzerland.

The preference is full or partial sun, moist to mesic conditions, and fertile loamy soil with high nitrogen content. This plant also adapts to gravelly and sandy soil.