Sweet wormwood (Artemisia annua)

About the plant

Sweet wormwood is an annual plant belonging to the same genus as common mugwort and tarragon – Artemisia. It grows from 30 to 200 cm (1 to 7 feet) tall and spreads wide to resemble a bush. The stem is smooth, upright, and branched, and its green color turns slightly brown over time.

Sweet wormwood leaves are 3 to 5 cm (1 to 2 inch) long and divided into two or three small leaves by deep notches. The medicinal plant bears small, round, greenish-yellow flowers with 2 to 2,5 mm (1/10 inch) diameters. The flowers are similar to those of the common mugwort.

A sweetish smell and a bitter taste characterize sweet wormwood.

Sweet wormwood originates from Asia. It is believed to have been used by the Chinese for thousands of years and was introduced to Europe by the Turks.

Where does it grow?

It grows naturally in many warm places worldwide. It is native to temperate Asia, but we usually cultivate it in gardens worldwide.

Sweet wormwood likes sunny and warm conditions to grow. Its optimum temperature for growth is between 20 and 25 °C. As a mature plant, it is pretty tolerant of different climatic conditions. Although the plant can adapt to varying soil types, the best soil is one through which water drains quickly.

When to harvest sweet wormwood?

Sweet wormwood is harvested at the beginning of flowering when the first flower buds – the flower spikes – form, as this is when it has the highest artemisinin content. It is usually in the northern hemisphere in August or September and depends on the site’s location.

Harvesting it in dry and sunny weather when the plant contains the most active substances is essential.

Which parts should we harvest?

You can harvest the whole plant and remove the thick stems. Leaves of sweet wormwood with flower buds are used for drying or further processing. It is preferable not to damage or tear/cut the leaves into small pieces before drying to avoid losing active substances.

How to dry sweet wormwood?

Dry plant parts at a temperature not higher than 40 °C; otherwise, its main active ingredient, artemisinin, would evaporate and be lost. Keep the leaves whole during storage and crush them only before using so that active ingredients are better preserved.

Medicinal effects

Sweet wormwood contains at least 20 active substances that help with various health conditions. The most studied are its positive effects on malaria. Treatment with its most important active ingredient artemisinin significantly reduces mortality in malaria patients.

Its anti-cancer effects are also being investigated. Artemisinin and its derivatives have cytotoxic effects against various types of cancer cells. The active substance artemisinin combines with iron to form oxygen-free radicals that destroy cancer cells. This effect has so far been observed in breast, pancreatic, colon, central nervous system, lung, prostate, ovarian and skin cancer cell lines. Its consumption is recommended as a support to conventional cancer treatment.

Sweet wormwood also helps with many other diseases and ailments. It helps with colds, flu, and viral illnesses, as well as treating jaundice (liver disease), herpes, fungal infections, prostate problems, and relieving abdominal cramps.

Sweet wormwood contains the active ingredient quercetin, which is anti-inflammatory, antibacterial and antifungal. Luteolin has an antioxidant role and is also anti-inflammatory. Sweet wormwood acts against a wide range of parasites.

It helps women during menstruation by relieving menstrual cramps and regulating irregular menstruation.

It reduces fever, lowers blood sugar levels in diabetics and strengthens the immune system.

How to use Artemisia annua?

The tea is used to boost immunity and to help treat colds, flu, viral illnesses, abdominal and menstrual cramps, and lower body temperature.

The hydrolat of sweet wormwood can be used as a medicinal cure by mixing 1 dl of the hydrolat in 9 dl of water and consuming the liquid in sips throughout the day. It is done for four days, followed by a two-day break. After one month, take a 1-week break before starting a new course. This treatment should last no longer than three months.

Skincare: Sweet wormwood hydrolates can be used as a natural tonic to cleanse the skin, to treat acne, as an after-shave tonic, to make creams and soaps, to add to baths and to prevent herpes (apply to the area where the herpes is beginning to form).

Sweet wormwood ointment helps with joint pain.

To support cancer treatment, it is recommended to take capsules of artemisinin, tincture, or essential oil of sweet wormwood, as the value of the active ingredients in such preparations is much higher than in tea. The destruction of cancer cells is thought to be most effective when combined with capsules of iron and vitamin C. Talk with your physician before you decide on that kind of treatment.

For menstrual cramps, use essential oil massaged over the abdomen at the site of the cramps.

Hang some sweet wormwood leaves and flowers on a string as insect repellent. You can also use sweet wormwood hydrolat to repel insects by applying it to the skin as a repellent.

Inhalation: inhale two drops of sweet wormwood essential oil in 2 dl of boiling water.

Scenting the room: hang sprigs of fresh sweet wormwood or put two drops of the essential oil in a vaporizer and enjoy the pleasant scents of sweet wormwood.

Making tea

Sweet wormwood tea can be prepared in two ways.

Tea infusion: pure 200 ml (one cup) of hot but not boiling water over 1 or 2 teaspoons of the dried and crushed herb. Leave to steep for 10-12 minutes, then strain the tea. This herbal infusion can be drunk twice a day.

Tea macerate: soak 1 to 2 teaspoons of dried sweet wormwood leaves in 200 ml (one cap) water for 12 hours and cover the cup or container at room temperature. After this time, you can heat tea to 60 °C before being strained. This method of preparation is preferable as more artemisinin is extracted.

Alternatively, combine both recipes to prepare tea. First, make the macerate, then take the strained herb and make the tea with fresh water. This time, make a tea infusion. Once the infusion has cooled down, mix two prepared liquids and drink throughout the day.

The tea or the water in which the herb is placed must never be heated above 70 °C (158 °F), as high temperatures can cause the loss of the active substances.

What should you pay attention to?

Sweet wormwood contains large amounts of pollen, which may irritate people who are allergic to it.

People with diabetes should be cautious when using sweet wormwood, as the plant lowers blood sugar levels, which can lead to hypoglycemia – state when blood sugar levels are lower than usual.

Before using sweet wormwood for medical treatment, consult a personal physician, especially for those taking any medications that may cause unwanted side effects when combined with sweet wormwood.

Growing sweet wormwood

The fact that sweet wormwood is an annual plant means that it needs to be re-sown every year. The time from planting the plant to harvesting the sweet wormwood ranges from 190 to 240 days.

The following instructions are written for continental climates with cold winters and warm summers (for example, central Europe). You may not need to make seedlings indoors, or you can even sow directly in the garden if winters are not cold in your climate.

Sweet wormwood is sown in pots or troughs in early spring. As the seeds are tiny, it is best to sow them only on the soil’s surface without burying them deeply. Then, use a sieve or a flour sifter to spread some soil or fine river sand over the soil’s surface.

It is best to add water only to the pot’s base at the beginning (so the pot needs to be slightly lower) so the soil draws the moisture upwards. Pouring water over the soil could damage the highly delicate plant or seedling, which will not pick up again. Place a transparent food film over the pot or trough to prevent the soil from losing moisture. Keep watering this way until the plant has grown at least 3 to 5 cm (1.2 to 2 inch).

Place the pots or troughs in a sunny place, preferably near a window and in a room with a temperature of about 21 °C (70 °F), but not near a radiator. Once the plant has germinated, it will start to turn towards the sun and, due to the weight of its leaves, it may fall and not pick itself up. Therefore, turning the pots twice daily is essential to keep the seedlings upright.

During the colder months, they are kept indoors and only replanted out into the garden in the late spring (May in Europe), when frost is no longer likely.

It is best to plant in rows as this makes weeding easier. One seedling per square meter of soil is recommended to be planted. As the plant grows very quickly, it is essential to give it a support to lean on once it has grown.

It is not required to fertilize sweet wormwood. However, if you choose to do so, add potassium as a primary fertilizer, as the plant takes up potassium throughout its growth; nitrogen can be helpful during the branching period and phosphate during the flowering phase. Phosphate fertilization can lead to a higher content of the active substance artemisinin.

Interesting facts

In 2015, Chinese scientist Dr Tu Youyou was awarded the Nobel Prize in Medicine for discovering artemisinin’s active ingredient in sweet wormwood.

Sweet wormwood is believed to have been introduced to European soil by the Turks, who used the plant to treat sick soldiers during their conquests.