Osborne Trail and Park Association


Yellow Wingstem

Verbesina alternifolia (L.)
Britton ex Kearney Asteraceae

Have you seen the tall yellow daisies growing throughout the park ravine? Meet the alluvial soil-loving Wingstem also called yellow ironweed. Growing 4-8.5 ft tall and blooming yellow in late August through September, wingstem is amongst the most populous herbaceous plants in MRRNP. It is a vigorous plant in rich, loose soil in full sun to part shade and may be considered too weedy for smaller gardens but it is a very valuable provider of floral resources for flower-visiting insects: bees, beetles, birds, butterflies, and myriad flies make use of the blooms. Wingstem also competes strongly with many exotic, invasive plants and can reduce or prevent their establishment in vulnerable areas.

Wingstem (BONAP map: http://bonap.net/MapGallery/County/Verbesina%20alternifolia.png) is found throughout the southern tier counties of PA, and north to Erie in the west. It can also be found in most moderate-to-high quality alluvial/riparian areas in Allegheny County.

The well-disguised caterpillar of the wavy-lined emerald moth not only feeds on Wingstem floral tissue but also attaches tatters of flowers to its body as an incredible camouflage! A real tatterpillar! Goldfinches also relish the seeds through autumn. Wingstem is also host to larva of Gold Moths, and Summer Azure and Silvery Checkerspot Butterflies. The dried stems of last year’s growths are hollowed out and used as home by various insects including small carpenter bees.

There are 16 other species of Wingstem in the USA, though yellow Wingstem is the only one found commonly in SW PA. The related Yellow Crownbeard (Verbesina helianthoides), a plant of xeric limestone woodlands and prairies, has recently been planted in the “under development” Barrens Gardens along the upper trail.

Wingstem seeds may be collected in October (if the finches have not eaten them all), winnowed and stored dry. Sixty days cool moist stratification (35F) followed by warmer temps (60 to 70F) results in germination with seedlings growing rapidly and achieving blooming size within 1 to 2 years.

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