ironweed Interesting Notes

The Summer’s Swan Song ironweed was selected from a cross of Vernonia lettermannii and V. angustifolia ‘Plum Peachy’. This was the first of our hybrid seedlings to catch our attention, and it never failed to impress in the subsequent trials. Similar in adaptability, bushiness, and fine texture to the popular selection Vernonia lettermannii ‘Iron Butterfly’, ‘Summer’s Swan Song’ grows somewhat larger, has larger capitula, and never lodges due to the elongated and interlocking inflorescence branches holding the stems together. -Chicagoland Grows

While waiting to be christened, ‘Summer’s Swan Song’ (V. ‘Summer’s Swan Song’) garnered a lot of attention as ‘20100308’ in our trials. Early on, we admired the deep red stems and purple-tinged, olive green leaves—the shape comes from narrowleaf ironweed and the coloring from ‘Plum Peachy’ tall ironweed (V. angustifolia ‘Plum Peachy’). Jim Ault of Chicago Botanic Garden (CBG) was the expert matchmaker. From early to midfall, deep purple flowers are plentiful on long, flowering branches—a unique trait of this cultivar. Unlike other ironweeds, the longer branches form an interlocking network that holds the stems upright on even the windiest days. ‘Summer’s Swan Song’ is the smallest of the hybrid cultivars right now, topping out at a compact 36 inches tall and 40 inches wide. The 1/3-inch-wide capitula with their dark purple florets are borne in profusion for five to six weeks from early September to mid-October in northern Illinois (USDA Zone 5). A diversity of butterflies, moths, and bees are attracted to the flowers. Despite the marginal cold-hardiness of ‘Plum Peachy’, ‘Summer’s Swan Song’ is hardy in Zones 4 to 9. - Chicago Botanic Garden

Vernonia 'Summer's Swan Song' Growing and Maintenance Tips

Grow Vernonia lettermannii in full sun and average to dry soils with good drainage. Periods of inundation are tolerated, but not heavy or saturated soils.

It has proven adaptable to both moist and dry soil, and has also exhibited excellent resistance to rust and powdery mildew. Use this selection individually or massed in perennial or mixed borders, in pollinator gardens, near lake edges and other moist sites as long as well-drained, in drier sites, and in any situation that calls for a midsized attractive and uniform perennial plant. -Chicagoland Grows

Good Substitutions

Vernonia 'Summer's Surrender'

Vernonia noveboracensis

Vernonia lettermannii 'Iron Butterfly'