Joe-Pye Weeds have leaves in whorls of 3 to 7 leaves on tall (from 3 to 7 feet) stout stems. Sweet-scented Joe-Pye Weed is a native erect perennial forb that has a solid stem, greenish, not spotted, with purple usually at the leaf nodes. The lower stem is usually without hair, the upper stem can have fine hair, including glandular hair, especially within the floral array. The plant has a vanilla scent when bruised, hence the common name.
Leaves are in whorls of 3 or 4, (sometimes 5) coarsely toothed, have a pinnate vein arrangement, with bases abruptly to gradually tapered. Lower stem leaves will have a stalk, upper leaves may be almost stalkless. The upper surfaces are usually without hair but the lower surface can range from sparsely hairy with gland dotting to densely hairy. The shapes vary from lanceolate to deltate-ovate.
The floral array is a dome shaped branched doubly compound array composed of individual corymbs (clusters of flowers that appear slightly domed to flat-topped due to varying stalk length of each flower in the cluster and each sub-branch of the cluster). Each sub-part of the overall array is composed of several individually stalked corymbs. There can be smaller axillary clusters from the upper leaf whorl.
Flowers: Each corymb has a varying number of flower heads. Within each flower head are 4 to 7 small florets that have 5 stamens with whitish anthers that surround a single style that is white, branched and protrudes from the floret throat. These florets are so slim that it appears the flower itself is a bunch of white styles. Each floret has a purple to pale pink tubular corolla (can occasionally be whitish in certain light conditions). The base of these florets form the seed. The flowerhead is cylindric in shape and on the outside there are 4 to 5 series of oblong phyllaries, the inner series longer, the outer shorter, usually pink in color at flowering time and occasionally hairy.
Seed: Fertile florets produce a dry 5-ribbed seed (a cypsela) with numerous long bristles for wind dispersion. Seeds require at least 30 days of cold stratification for gemination and germinate best in cool soils.
Varieties: There are two accepted varieties of E. purpureum - var. purpureum where the lower leaf surface is without hair or only hairy along the major veins and var. holzineri where the lower leaf surface is densely hairy. Minnesota authorities report only the latter is found in Minnesota. Some references state that var. purpureum is in Minnesota but the U of M Herbarium reports none have ever been collected.
Habitat: Sweet Scented Joe-Pye Weed grows from a fibrous root system in meadows, open woods with full to partial sun, moderate to dry moisture conditions and loamy soil. This is a native plant that grows well in the home garden as a backdrop specimen. While it will grow in partial sun, stems will be weaker and it will tend to lean toward bright light.
Names: An older scientific name for this species was Eupatorium purpureum L., but recently, botanists have reclassified the species from the genus Eupatorium. The newly assigned genus has plants of the Aster family with whorled leaves and unequal phyllaries. It exclusively holds, in North America, the Joe-Pye Weeds of which there are five. The name, Eutrochium , is derived from the Greek eu, meaning 'well' or 'truly' and trocho, meaning 'wheel-like', together referring to the whorled leaves. The species name, purpureum, is Latin for 'purple' or 'mottled'. The older genus name has a quite interesting story and that is found below along with the common name descriptions.
The author names for the plant classification are: (L.) - refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. He was the first to classify in 1753. There were other updates over the years but the last update and the new genus assignment in 2004 was by ‘E.E.Lamont’ which is for Eric E. Lamont, American Botanist and Research Associate at the New York Botanical Garden who has published Taxonomy of Eupatorium Section Verticillata (Asteraceae), 1995, New York Botanical Garden Press.
Comparisons: Sweet-scented Joe-Pye Weed has differences in the stem and in the flower arrangement from its relative, Spotted Joe-Pye Weed, Eutrochium maculatum, which prefers a more moist habitat.
Above: The plant is erect with leaves below the inflorescence in whorls of 3 or 4. The inflorescence is a dome shaped branched doubly compound array composed of individual corymbs
Below: 1st photo - Leaves have a pinnate vein arrangement, with bases abruptly to gradually tapered. Lower stem leaves will have a stalk, upper leaves may be almost stalkless. 2nd photo - The lower surface can range from sparsely hairy with gland dotting to densely hairy as in var. holzineri. The shapes vary from lanceolate to deltate-ovate.
Below: 1st photo - The stem is usually greenish with purple only at the leaf nodes and close to and in the floral array there are fine hair. 2nd photo - The phyllaries of the flower heads are in several series, the outer shorter. During flowering they are pink as shown here. 3rd photo - Six florets from a flower head with styles still present and achenes developing.
Below: 1st photo - The phyllaries of the flower heads, shown here in the fall when they lose the pink color. 2nd photo - The seeds are long and pointed with 5 ribs and with long fine bristles attached for wind dispersion.
Below: 1st photo - There are several small leafy bracts under the floral array. 2nd photo - Autumn seed heads.
Below: The root system is fibrous.
Notes: Sweet-scented Joe-Pye weed is indigenous to the Garden. Eloise Butler noted it in her Garden Log on Sept. 6, 1907 and noted it in bloom on several occasions: Aug. 2, 1910 and July 4, 1914. She made no record in her log of planting it. This plant was not listed on Martha Crone's 1951 inventory of plants in the Garden at that time but was added again in later years. Susan Wilkins planted it in 2011. It is native to a few counties in Minnesota in the NE section of the state and to counties in the SE quadrant including some metro countries but wild native plant surveys do not include it in Hennepin, Scott or Anoka, which is strange based on Miss Butler's notes. In North America it is found in the wild from the Central States eastward (excluding the Dakotas and Texas) and in the province of Ontario. It has far less distribution within Minnesota and in North America than the Spotted Joe-Pye Weed, Eutrochium maculatum. The two Joe-Pye Weeds are the only representatives of the genus found in Minnesota.
The common name seems to have the following consensus: The name could have come from an Indian medicine man in colonial New England known as “Joe Pye”. He had fame in using this plant to cure typhoid and several other diseases; or, since an Indian word for typhoid is “jopi”, the plant used to cure typhoid became the jopi weed which eventually worked it way into “Joe Pye.” Take your pick. In some parts of the country the plant is referred to as Queen of the Meadow, but we in Minnesota know a different plant by that name. Gravelroot is a name frequently found in old books, particularly those from Britain.
The older scientific name, Eupatorium, came from Mithridates Eupator the ruler of Pontus in old Asia Minor, who lived from 135-63 BC. He was the sixth in his line and was aware that the principal method of disposing of ones enemies in those days was by poison so he began using plants in his medicine and in his personal quest to become insensitive to poisons. By ingesting a slight amount of plant poisons each day along with various plant based antidotes, Mithridates was able to build an immunity to many poisons, such that when he wished to commit suicide following his defeat, poison would no longer work and he had to have a military associate slay him by the sword. Long a friend of Rome, he had gone his own way, defeating two prominent Roman generals in the process, but in 63 BC he was finally defeated in his own kingdom of Pontus by Gnaeus Pompeius Magnus, which battle earned Pompey the title “Pompey the Great,” who then was later associated with Julius Caesar in the First Triumvirate.
Lore and Uses: (Applies to both Spotted and Sweet Joe-Pye Weed) The plant root is the main medicinal part of the plant as it contains some volatile oils and thus when powdered or made into a fluid extract, can be used as a diuretic and for internal ailments. The root is slightly bitter with an aromatic taste and slightly astringent. A decoction of the root is a remedy for problems of the bladder, kidney or urinary system (Hutchins Ref. #12). Densmore (Ref. #5) reports the Chippewa put some of the decoction in a fretful child's bath and sleep would be induced. The working compound in the root is Euparin with the chemical formula C12-H11-O3. Hot teas were made from the leaves and these were said to produce sweating to break a fever. The use of crushed leaves were said to improve the complexion and one legend has it that a young brave courting a young women was “assured” of success if he stuck a wad of the leaves in his mouth before he went visiting. Perhaps it had mouthwash effects as the leaves have a vanilla scent when crushed.
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"