Crooked Run Valley
hyssopleaf thoroughwort (Eupatorium hyssopifolium)
SCIENTIFIC SYNONYMS: There are no scientific synonyms for Eupatorium hyssopifolium.
TAXONOMY: The currently accepted scientific name of hyssopleaf thoroughwort is Eupatorium hyssopifolium L.
There are three varities of Eupatorium hyssopifolium: 1) calcaratum Fernald & B.G. Schub., 2) hyssopifolium, and 3) laciniatum A. Gray. All three occur in Virginia and all three are known as hyssopleaf thoroughwort.
NATIVE STATUS: Native, United States.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: This is a perennial herbaceous plant, which can reach 150cm in height (60inches). Short leafy branches start at almost every leaf axis but only extent as true branches near the top of the main stem. Stems arise from short caudices or rhizomes, stems single pubescent throughout.
Leaves: The leaves are whorled. Some of the leaves are alternate and some whorles have three leaves and some four. Leaves usually opposite or whorled (distal sometimes alternate, spreading or horizontal); simple, sessile; blades 3-nerved from bases (laterals sometimes weak), lance-linear, lance-oblong, or linear, 20–60 × 2–15 mm (lengths mostly 6–40 times widths). The bases are cuneate, margins entire, laciniate-serrate, or serrate, apices acute, faces scabrous (at least abaxial). Axillary buds to produce leaves without expansion of shoots; the combination of whorled leaves and suppressed axillary shoots gives the nodes a somewhat tufted or verticillate appearance.
Flowers: Like other members of the genus Eupatorium it has inflorescences containing a large number of white flowers with disc florets and no ray florets. The flowers are tiny, fringed, erect white tube, 1/4 in (6 mm) wide in a light, airy, flat-topped terminal cluster of many flowerheads. The flowers are fragrant.
Fruit/Seed: Fruit: small dry seed with white fluffy bristles.
Roots: Hyssopleaf thoroughwort has short caudices or rhizomes.
REGENERATION PROCESS: Hyssopleaf thoroughwort propogates itself by reseeding.
HABITAT TYPES: Open, well-drained sites: fields, meadows, roadsides, borders and open woods, salt meadows, disturbed areas.
SITE CHARACTERISTICS: Hyssopleaf thoroughwort prefers full sun to grows in a variety of soil types but requires good drainage.
SEASONAL DEVELOPMENT: Blooms first appear in late summer and continue into mid fall (July to November).
GENERAL DISTRIBUTION: Hyssopleaf thoroughwort occurs from Florida north to Massachusetts, and west to Texas in the south, and north through Arkansas, Missouri, and Illinois. It does not naturally occur in Canada.
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: Field reports state that long-tongued bees (e.g., Ceratina calcarata) visit hyssopleaf thoroughwort while some short-tongued bees (e.g., Augochlorella aurata) also visit it.