Joe-Pye Weeds have leaves in whorls of 3 to 7 leaves on tall (from 3 to 7 feet) stout stems. Spotted Joe-Pye Weed is a native erect perennial forb with a solid stem that has purple spotting or is sometimes uniformly purple. The base area of the stem can be smooth and free of hair but the upper portions and within the floral array are usually hairy with some glandular hair in the upper section.
Leaves are coarsely toothed, ovate to ovate-lanceolate in shape, gradually or abruptly tapering to a short stalk. The leaves are in whorls of 4 to 5 (but can be 3 or up to 6). They are pinnately veined with a single main vein and tapered tip. The upper surface can be smooth to slightly hairy. The underside can be almost smooth but is usually densely hairy and gland-dotted.
The floral array is a rounded to slightly depressed compound array of small flat-topped flower clusters (corymbs) with each small cluster being part of a larger array and the larger arrays forming the inflorescence. There can be smaller arrays rising from the upper leaf axils.
Flowers: Each corymb has a varying number of flower heads. Within each flower head are 9 to 20 (can be 8 to 22) small florets that have 5 stamens with whitish anthers and a 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 purplish tubular corolla. The base of these florets form the seed. The flowerhead is cylindric in shape and has 4 to 5 series of oblong phyllaries, the inner series longer, the outer shorter, usually pink to purplish in color and may be hairy or smooth.
Seed: Fertile florets produce a dry 5-ribbed seed (a cypsela) with numerous long bristles for wind dispersion.
Varieties: There are two accepted varieties of E. maculatum found in Minnesota today - var. bruneri where the stems are densely hairy throughout; and var. maculatum where the lower stem is smooth and free of hair, but the floral array may have very fine stem hair, and the upper leaf whorl is less wide than the floral array. A third variety, var. foliosum, once existed in Minnesota, known from Cook County, but has not been collected since 1945. The variety is similar to var. maculatum but has the upper leaf whorl equal to or surpassing the width of the floral array.
Habitat: Spotted Joe-Pye Weed prefers full sun in the wet to moist soil of meadows, marshes, shorelines. It has a fibrous and rhizomatous root system. This is a native plant that grows well in the home garden as a backdrop specimen if you have a moist area. Single plants will grow into nice clumps in just a few years. Plants can be divided in the fall or seed planted in the fall. The purplish blooms are attractive to butterflies, particularly swallowtails.
Names: The former name for this species was Eupatorium maculatum. Botanists have recently moved the plant into the genus Eutrochium from Eupatorium. The new name is derived from the Greek eu, meaning 'well' or 'truly' and trocho, meaning 'wheel-like', together referring to the whorled leaves. The species name, maculatum, is Latin for 'spotted'. The older genus name has a quite interesting story and that is found at the base of the page 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. His work was updated 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). New York Botanical Garden Press.
Comparisons: The other common Joe-Pye Weed is Eupatorium purpureum L. (Sweet-scented Joe-Pye Weed) which has fewer flowers per cluster and no spots on the stem, but can have purple at the stem nodes.
Above: A nice clump of Spotted Joe-Pye Weed.
Below: 1st & 2nd photos - Flower heads can be pink to purplish, somewhat rounded to depressed flat-topped as shown further below. 3rd photo - The stem can be purple to purple spotted, smooth as in var. maculatum as shown or densely hairy in var. bruneri.
Below: 1st photo - The floral array is a rounded to slightly depressed compound array of small flat-topped flower clusters (corymbs). 2nd photo - The toothed leaves are usually in whorls of 4 to 5 but can be 3 or up to 6.
Below: 1st photo - Stems of both varieties have fine hair in the area of the inflorescence. 2nd photo - The phyllaries of the flower heads are in several series, the inner longer. Shown here in autumn, they are pinkish-purple during flowering.
Below: The upper surface of the leaf - 1st photo - is medium green and usually smooth, where as the underside - 2nd photo - is pale in color with fine whitish hair, with gland dotting.
Below: The individual florets contained within a single flower number 9 to 20 - here 13.
Below: Seed heads and individual seeds, which are ribbed and have pointed tips and long bristles attached for wind dispersion.
Notes: Eloise Butler had catalogued this plant in her plant index as present in the Garden in 1932, although it was probably in the Garden much earlier as she noted on Aug. 2, 1910 that the three Eupatoriums were beginning to bloom. The other two would have been Sweet-scented Joe-Pye Weed and Boneset. It is native to Minnesota in a number of scattered counties, generally in the northern 2/3rds of the state. In North America it is found in all the lower Canadian Provinces and all the lower 48 except the the far south from Texas eastward to the Coast and absent in OR, CA and NV. It has far more distribution within Minnesota and in North America than the Sweet-scented Joe-Pye Weed, Eutrochium purpureum. 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 scientific name given above is a new classification for this plant. The older name was Eupatorium maculatum. That old generic name, Eupatorium, came from a Persian general, one Mithridates Eupator, who is said to have used plants as a medicine and in his personal quest to become insensitive to poisons. By ingesting a slight amount of plant poisons each day along with various antidotes, Mithridates was able to build an immunity to many poisons, such that when he wished to commit suicide, poison would no longer work and he had to have his servant slay him by the sword. Mithridates died in 63 B.C. Long a friend of Rome, they moved apart and he was finally defeated in his own kingdom of Pontus in Asia Minor by Pompey, which battle earned Pompey the title “Pompey the Great.”
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 of the Sweet-scented 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.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"