spotted joe pye weed (Eutrochium maculatum)
spotted joe pye weed
Eupatoriadelphus maculatus (L.) R.M. King & H. Rob.
Eupatorium maculatum L.
Eupatorium purpureum L. var. maculatum (L.) Darl.
TAXONOMY: The currently accepted scientific name for spotted joe
pye weed is Eutrochium maculatum (L.) E.E. Lamont.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: This perennial plant is 3-5' tall and unbranched, except for flowerhead-bearing stalks near the apex of the plant. The central stem is stout, terete, and either purple-spotted or purple; it is often covered with short fine hairs.
Leaves: At intervals along the central stem, there are whorls of 4-5 leaves that are yellowish green or green. These leaves are up to 7" long and 2½" across; they are lanceolate to broadly elliptic and serrated along their margins. The upper leaf sur-
faces have conspicuous venation. The petioles of the leaves are short (less than ¼" in length).
Flowers: The central stem terminates in a rather flat-headed panicle of flower-
heads spanning 3-6" across. Small clusters of flowerheads may occur below on separate stalks. Each narrow flowerhead is about 1/3" long, consisting of 8-20 pink to purplish pink disk florets and no ray florets. Each tiny disk floret has a narrowly tubular corolla with 5 spreading lobes along its upper rim; exerted from the corolla, there is a strongly exerted style that is divided into filiform parts. The narrow bracts (phyllaries) at the base of each flowerhead are pink or purplish pink, like the disk florets. The flowerheads are often fragrant.
Fruit/Seeds: The florets are replaced by achenes with small tufts of bristly hair; they are dispersed by the wind. Seeds are slender, 3 to 4 millimeters long, 5-sided with distinct ridges on the angles.
Roots: The root system is fibrous and rhizomatous. This plant often forms small clonal colonies.
REGENERATION PROCESS: The flower heads turn into a mass of brown seed, each with a tuft of light brown hair to carry them off in the wind.
HABITAT TYPES: Habitats include wet black soil prairies, wet sand prairies, sedge meadows, marshes, fens, and swampy thickets with small trees or shrubs. Spotted joe pye weed is partial to sandy wetlands, but it is also found in non-sandy wetlands. It is usually found in high quality natural areas, rather than degraded habitats with a history of disturbance.
SITE CHARACTERISTICS: Spotted joe pye weed prefers full or partial sun, wet to moist conditions, and a mineral-rich soil containing silty or sandy loam.
SEASONAL DEVELOPMENT: The blooming period occurs from mid- to late summer, lasting about 3-4 weeks.
GENERAL DISTRIBUTION: Spotted joe pye weed is found throughout
most of the United States and Canada with the exception of the Deep South/
Gulf Coast states (except Georgia) and the far western Pacific states.
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: The nectar of the flowers attracts honey bees, bumblebees, digger bees (Melissodes spp.), leaf-cutting bees (Megachile spp.),
bee flies, butterflies, skippers, and moths. Some bees may also collect pollen.
The following leaf beetles have been observed to feed on spotted joe pye weed: Exema dispar, Ophraella notata, and Sumitrosis inaequalis. An uncommon
aphid, Aphis vernoniae, sucks the plant juices. The caterpillars of some moth species feed on various parts of Eupatoriadelphus spp. (joe pye weed species). They include Schinia trifascia (three-lined flower moth; feeds on florets), Car-
menta bassiformis (eupatorium borer moth; bores through roots), Phragmatobia fuliginosa (ruby tiger moth; feeds on foliage), and Eupithecia miserulata (com-
mon pug; feeds on florets). The seeds of joe pye weed species are a minor source of food to the swamp sparrow. The foliage is not preferred as a food source for mammalian herbivores, although it may be browsed upon occasion by deer, rab-bits, or livestock.
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