Vernonia ‘Southern Cross’ Brings Late-Summer Color to the Garden

Vernonia ‘Southern Cross’, a hybrid ironweed, bursts into bright bloom in late summer and early fall, feeding butterflies, bees and other pollinators as the growing season ends. 

Common name: ‘Southern Cross’ ironweed

Botanical name: Vernonia ‘Southern Cross’

Exposure: Full sun

Season: Late summer and autumn, for flowers

Flowers: Frizzy, bright purple blossoms open atop the stems from late summer into early fall.

Related: Get fall combo ideas in "Pair Late-Season Blue Flowers With Foliage Plants"

Foliage: Threadlike, medium green leaves line the upright stems, providing a fine texture reminiscent of Arkansas bluestar (Amsonia hubrichtii) and threadleaf coreopsis (Coreopsis verticillata).

Related: Read about Arkansas bluestar in "5 Shrubby Plants With Golden Fall Foliage"

Size and habit: Vernonia ‘Southern Cross’ grows to about four feet tall and wide, a mass of upright stems covered with short, slender leaves. It has a dense, upright shape overall.

Origins: ‘Southern Cross’ is a hybrid between Vernonia lettermanii and an unknown species. It was discovered by Brent Horvath of Intrinsic Perennials. Vernonia lettermanii is native to western Arkansas and eastern Oklahoma, where it grows in gritty soil and rock crevices above the Ouachita River.

Related: Read about another Brent Horvath discovery, the award-winning Rudbeckia 'American Gold Rush'.

How to grow Vernonia ‘Southern Cross’: Site this perennial plant in full sun and any type of soil that has good drainage. It requires consistent moisture while it is getting established in the garden, but after its first season it prefers drier soil. Cut the previous year’s growth down to just above the ground in early spring. USDA Zones 4–9.

Image courtesy of Walters Gardens