Herbs and Spices
Feverfew (Tanacetum parthenium, formerly known as Chrysanthemumparthenium, Matricaria parthenoides), a member of the Asteraceae (Daisy Family), is an herbaceous perennial or annual crop. Its native habitat is southern Europe, but it has become naturalized throughout Europe, Asia, North Africa, Australia and North America . In Saskatchewan, selections of feverfew as an ornamental plant can be found in home gardens; only recently has it been grown here as a medicinal crop. Other close relatives of feverfew are chrysanthemum, pyrethrum and ox-eye daisy.
Feverfew (Tanacetum parthenium), a member of the Asteracea (Daisy Family), is an herbaceous perennial or annual crop.
Feverfew has been grown for over 2,000 years, and several varieties are currently in commerce. The wild type, commonly grown for medicinal purposes, is an erect, well-branched and leafy plant. It ranges in height from 30 - 90 cm (1-3 ft.). Leaves are usually under 7.5 cm (3 in.) in length, and often much shorter on the upper stems. They are cut into sharp-pointed lobes, nearly hairless and strongly aromatic.
The flowers are numerous and in terminal clusters. Individual flower heads are about 2 cm (3/4 in.) in diameter, and are daisy-like, with yellow disk florets in the centre and a single row of white ray florets on the margins. The flowers produce seeds readily. Horticultural selections of feverfew are often much shorter in stature and have flowers with double ray florets, which may be entirely white or yellow. Feverfew will bloom the first season of growth if planted early. In Saskatchewan, however, the plants usually die over winter. Therefore feverfew should be considered an annual.
It is not known when feverfew first became used for medicinal purposes. However, it was documented by Dioscorides, a Greek herbalist, in the first century A.D., as being valuable for inflammation and swellings. Since then, it has had a multitude of uses. As the name suggests, feverfew was commonly used to treat fevers, but at one time it was also used to treat stomachaches, toothaches, insect bites, colds and worms. More recently, it has been used as a sedative to treat asthma, arthritis, rheumatism, migraine and gynecological problems. Particularly popular in Europe, it is now more widely used than aspirin for treating migraine and arthritis.
Herbal products containing feverfew consist of dried leaves or dried aerial parts. They are readily available on the market in the form of standardized or unstandardized capsules, tablets and fluid extracts, as well as in dried form such as herbal tea and occasionally as a crude unprocessed herbal product.
Feverfew contains sesquiterpene lactones, of which parthenolide (0.1 - 0.9%) is the most important constituent. Various other compounds have been identified, but in significantly smaller amounts. Research is ongoing. It has been found that the composition of feverfew varies, depending on the source of plant material. In some instances, feverfew products sold in North American health food stores were found to contain little or no parthenolide. Not less than 0.2 per cent parthenolide should be contained in feverfew products. Recommended daily dose of this herb should be equivalent to 0.2 - 0.6 mg of parthenolide.
Feverfew, in its cultivated forms, is used as a landscape plant, and to some extent as a dried floral crop. It is not used extensively as a fresh cut flower because of the pungent odour of the foliage.
Hazards of Use
While feverfew has been used for centuries, the effects of long-term use have not been documented. Recent studies indicate that about 18 per cent of feverfew users have reported some adverse effects. The most widely reported symptom is mouth and tongue ulceration upon use of both fresh leaves and capsules is, followed by gastric problems. However, both symptoms are of low incidence. In rare cases, a contact allergy has also been reported. Use of feverfew during pregnancy should be avoided.
Propagation by Seed
Seeds may be sown directly outdoors in spring, or started indoors. Seedling plugs are also available from wholesale greenhouse producers.
There are about 5,200 seeds/gram. The seeds may be started indoors about two weeks before the last frost is anticipated, or 10 to 12 weeks before anticipated transplanting time. The seed should be sown on the surface of the growing medium and pressed in without covering, as light benefits germination. Warmth (21 C) will also promote germination. Typically, 85 per cent of fresh seed should germinate within five to 15 days. The plants may be transplanted outdoors when they have four true leaves, spacing them 15 - 45 cm (6 -18in.) apart in rows. Row spacings of 60 cm or more can be used, depending on cultivation equipment. Alternatively, the plants can be sown directly outdoors in a coldframe, and later transplanted, but germination will be slower. Direct field seeding on a large scale is difficult, because of the small seed size and the need to plant it shallowly and keep it moist until germinated.
In areas where the plants overwinter, roots may be divided in early spring into three to 15 divisions, according to size of the parent root. Alternatively, basal heel cuttings (with part of the old stem/root attached) can be taken in fall or spring, the tops shortened and allowed to root in a light growing media in a shady location. For commercial purposes, seed production is normally used.
Field Site and Culture
Feverfew should be grown in well-drained soil in a sunny location, although it is somewhat shade tolerant. The plant is quite adaptable to most soil types. Fertility requirements have not been established yet, but it has been suggested that yields will be higher in fertile soils. Research at Outlook, however, suggests that additional nitrogen and phosphorus may decrease parthenolide content in the plants. Currently, there are no registered herbicides for this crop. At Outlook, Prince Albert and Tisdale, trials indicated that feverfew adapts well to culture with plastic mulch. Once established, the plants require only minimal care. Feverfew can tolerate some drought, but irrigation may be necessary in certain years for higher production and to facilitate transplanting. At Outlook, a higher planting density of 111,000 plants/ha gave superior yield over a planting density of 55,000 plants/ha under both dryland and irrigated conditions.
Disease and insect problems are not well documented in Saskatchewan. Chlorosis of foliage may occur on poorly drained and/or very alkaline soil. Aster yellows disease, spread by leafhoppers, may be a problem in some areas. Symptoms include stunting, discolored foliage, shoot proliferation and malformed or off-coloured (usually green-coloured ) flowers. Roguing of affected plants will help control the spread, as will the control of leafhoppers. Feverfew should be grown away from other crops such as caraway and echinacea, which are known to be susceptible to aster yellows disease.
Feverfew should be harvested in the early stage of full bloom. Most buyers prefer the top 50 per cent of aerial parts. Some companies prefer only the top leaves and flowers, with little stem material. Others prefer leaves only. The plants may be harvested similar to alfalfa, using a forage harvester. Rinsing the crop in water, with two per cent hydrogen peroxide, for 10 minutes, may be desirable to remove dust and destroy microorganisms. The plant material should be handled as little as possible after cutting to minimize bruising, which can encourage browning and growth of microorganisms. Feverfew should not be dried in hot sunshine, but rather under cloudy or overcast conditions in order to preserve the active compounds it contains. If this is not possible, a kiln or solar dryer, at temperatures up to 60 C, should be used for drying. Whichever method is used, the plant material should be spread in a thin layer to facilitate rapid drying. The moisture level should be reduced to about 10 per cent moisture. Following drying, the material is bagged for shipping. It should be stored in a dark, dry and cool place, well away from other herbs because of its strong penetrating aroma. Due to suspected instability of parthenolide, feverfew should be sold and used within six to 12 months after harvest.
Costs of Production
The economics of production in Saskatchewan has not been documented. In 2009, feverfew seed was sold for $424/kg, while feverfew plugs were available for approximately $0.40 per plant. In 2009, buyer prices for dried feverfew was about $7.00/lb or $3.20/kg. Premiums paid for organically produced product in Canada have fluctuated from year to year and are buyer dependent. Yields of feverfew in Saskatchewan can vary from 2,000 kg/ha (1,800 lb./ac.) to 5,000 kg/ha (4,450 lb./ac.) dry herb, depending on planting density, rainfall and/or use of irrigation.
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