Artemisia annua Seeds | Sweet Annie Sagewort Wormwood
LATIN NAME: Artemisia annua
COMMON NAME: Sweet Annie
Plant Profile
Sweet Annie is a fast, upright annual, 1-2 m tall, with finely cut, fern-like leaves and tiny yellow-green flower heads in loose panicles. The whole plant smells sharply of camphor and wormwood, and the scent clings to hands and clothes after handling.
It is grown for the herb, for the dried foliage in wreaths, and as the source of artemisinin, the antimalarial compound that changed global medicine. Plants are rangy and need space; a single specimen will fill a square metre by August and self-sow across a garden.
Artemisia annua comes from temperate Asia, including China and Vietnam, and it is now naturalised across Europe and North America. It grows on disturbed ground and riverbanks, and it flowers in late summer, setting enormous quantities of tiny seed.
Science & Biotechnology
Artemisinin is a sesquiterpene lactone with an endoperoxide bridge, and that bridge is the active part: it reacts with iron in the parasite and releases free radicals that kill it. The compound was isolated in China in the 1970s by Tu Youyou, who received the Nobel Prize in Physiology or Medicine in 2015 for the work.
Artemisinin alone is no longer used to treat malaria, because resistance develops quickly. The standard is artemisinin-based combination therapy, pairing a fast-acting artemisinin derivative with a partner drug that clears the remaining parasites. The World Health Organization explicitly warns against treating malaria with the dried herb or with home-made tea, both because the dose is unreliable and because partial treatment drives resistance.
The plant’s artemisinin content is low, around 0.1 to 1 per cent of dry weight depending on the strain, and it varies with harvest time, altitude and day length. Breeding for higher content and for earlier flowering has been a major research effort, since the world supply of the drug depends on the crop.
Uses & Benefits
The dried foliage is used in wreaths, in dried arrangements and in potpourri, where its scent lasts for years. In Chinese practice the herb is used for fever, and the dried plant is burned as a mosquito repellent in some regions.
In the garden the plant is grown for its texture and its scent, and as a companion plant whose volatiles are said to deter some pests. Commercially the crop is grown for artemisinin extraction, and the seed is sold to herb growers and to dried-flower producers. It is not a plant to self-treat with, and the dried herb is not a substitute for antimalarial medicine.
Growing from Seed
Sow on the surface in early spring, since the seed is tiny and needs light. Germination takes ten days to three weeks at 18-20°C. Do not cover the seed, and water from below to avoid washing it away.
Plant out at 50 cm apart in full sun and ordinary, well-drained soil. The plant needs no feeding and will flop in rich ground. Pinch once when young for a bushier habit, and harvest the foliage before flowering for the highest artemisinin content. Leave a few plants to seed if you want the colony to return, since self-sowing is reliable in bare soil.
Our Take
A plant worth growing for the scent and the history, and one to respect for what it is: a drug crop, not a home remedy.
Related Reading
Gardeners who grow Sweet Annie often pair it with these related subjects: