Feverfew is an introduced and adventive erect perennial forb, growing from 8 to 24+ inches high on stems that are sometimes ridged and with branching and are usually smooth but may have some sparse hair in the upper parts.
The leaves are alternate and are all stalked stem leaves - no basal leaves. They are somewhat ovate to a rounded delta in overall shape and 1 to 2 pinnately lobed into 3 to 5 pairs of ovate shaped primary lobes. These primary lobes are usually deeply indented or coarsely toothed on the margins. Leaves tend to be a yellow-green color, with the midrib flattened on top and convex below. Leaves become progressively smaller toward the top of the stem and those uppermost leaves may be sessile. Leaf surfaces are usually gland-dotted and the underside normally have very fine hair. A crushed leaf produces a strongly aromatic odor.
The floral array is a grouping of 5 to 20+ flower heads, with flower heads divided into one or more flat-topped stalked arrays (corymbiform design). There are small leaf-like bracts at the base of each array.
Flowers: Each flower has a 1/4 inch (7mm) wide, hemispheric base from which rise 2 types of florets - ray florets and disc florets. The outer ray florets number 10 to 21+ and have white corollas and rays, are pistillate (female) and fertile. The rays have several prominent ribs which create a blunt shallowly lobed tip on the ray. The center disc has numerous yellow disc florets, appearing yellow-green to yellow until they open. These are bisexual and fertile with 4 to 5 pointed lobes on the corolla. Five stamens surround a single style. The whole center is flat - like a button, but not so much as in Tansy, T. vulgare. The outside of the flower head has several series of lanceolate shaped phyllaries, unequal in size, with pointed tips that are dark green whereas the remainder is a very light green. These persist onto the seed head.
Seed: Fertile flowers produce a dry columnar cypsela (the seed) with 5 to 10 ribs, 1 to 2mm long that lacks pappus but has a short toothed crown. These are still light enough to be wind dispersed.
Habitat: Feverfew grows from a rhizomatous root system which spread the plant vegetatively. It takes root in disturbed areas, roadsides and areas near gardens from which it has escaped. When the area is cultivated, small root sections remaining can still form new plants. It does best in full sun but plants in light shade will still flower but be smaller. Successive cuttings will weaken the root system and eventually kill it, or if you don't want to use herbicide, hot brine or Caustic Soda used to do the job in older days. It needs at least partial sun and tolerates soils with moist to slightly dry moisture conditions.
Names: The common name of Feverfew is derived from the Latin word febrifugia meaning 'to reduce fever' and is a reference to the medicinal use for treating fever. The genus Tanacetum according to Stern (Ref. #37a) is from the Medieval Latin tanazita, a word still used in some European areas. This name may have been derived from the Greek athanasia, for 'immortality' as plants of this genus were used in ancient times within funeral winding sheets to discourage worms. The species name, parthenium, is the old Greek word for the plant - said to be in reference to the use of the plant to save the life of someone who had fallen from the Parthenon while it was under construction. Years ago the plant was classified as Matricaria parthenium. The plant classification author (following the original description of Linnaeus (L.)), ‘Sch.Bip.” refers to Carl Heinrich ‘Bipontinus’ Schultz (1805-1867) German physician and botanist wrote several botanical works particularly on the Aster family.
Comparisons: There are 4 species of Tanacetum in North America, 2 of which are in Minnesota and that one, Tansy, T. vulgare, has disc florets only but of two types, both with yellow corollas. The leaves of Tansy are more divided than in Feverfew.
Above: The flowers in the floral array are divided into a grouping of flat-topped clusters at the top of the branching stem.
Below: 1st photo - The flower head has outer ray florets, female only, and a center of disc florets which are bisexual. 2nd photo - The flower head has several series of lanceolate shaped phyllaries, unequal in size, with dark green pointed tips.
Below: 1st photo - Detail of the disc florets. These can be yellow-green to yellow before opening. 2nd photo - upper stem section showing some fine hair.
Below: Leaves - While the leaves are all stem leaves, the lower ones (1st photo) have longer stalks and more segments. The very upper leaves will be stalkless. A yellow-green color (2nd photo) is common.
Below: 1st photo - The convex veins are prominent on the underside of the leaf where there is fine hair. Note also the gland-dotting on the underside. 2nd photo - Seeds are a dry columnar ribbed cypsela (like an achene) with a short toothed crown.
Notes: Feverfew has been naturalized in Minnesota. It is also planted in herb gardens. The DNR does not provide a county by county location breakdown. It is found in most of North America except the central plains area and the southern border from AZ to FL. In Canada is is absent in the Central plains and the northern Provinces.
There are two species of Tanacetum found in Minnesota, Tansy, T. vulgare and T. parthenium, Feverfew; both were introduced and invasive. Tansy is much more widespread, found in over half the counties of the state, with most exceptions in the southern half. In North America Tansy is found throughout except for 5 states near the Gulf Coast and two northern Canadian Provinces.
Uses: Feverfew has seen both practical and medicinal use as have most of the Tanacetum genus. Feverfew is known for its tonic and fever-reducing properties. The main active ingredients are the 30 sesquiterpene lactones of which parthenolide is of most importance; then there are 23 compounds of volatile oils and a number of flavoniods of which tanetin is important. The leaves are the primary plant part used and they need to be collected before flowering time; the flowers and the seeds also provide some of the chemicals. A decoction made with honey or sugar was used for coughs and difficult breathing. As a general tonic, an ounce of leaves was added to a pint of boiling water and when cooled taken in half teacup doses. As for insect bites, a tincture applied locally was quite effective. Treatment of migraine, arthritis and nausea were other uses. Documentation of use of this species goes as far back as Dioscorides in the first century. For a review of the Pharmacological Properties of Feverfew see this article from Pharmacognosy Review.
Gerard wrote in his Herball of 1597 (Ref. #6a): "It is a great remedie against the diseases of the matrix; it procureth womens sickness with speed. . . Dioscorides also teacheth that is is profitablie applied to Saint Anthonies fire, to all inflammations, and hot swelligs, if it be laide unto both flowers and leaves. . . Feverfew dried and made into powder, and two drams of it taken with honie or sweete wine, purgeth by fiege melancholie and flegme; wherefore it is good for them that are giddie in the head, or which have the tuning called Vertigo, that is a swimming and turning in the head. Also it is good for such as be melancholike, sad, pensive, and without speech."
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"