Ironweed ‘Summer’s Swan Song’

* Common name: Ironweed ‘Summer’s Swan Song’

* Botanical name: Vernonia ‘Summer’s Swan Song’

* What it is: Ironweed is a late-summer/early-fall purple-blooming perennial flower that doesn’t show up in many gardens, mainly because it’s so tall (five feet and up), prone to leaning, and susceptible to rust and mildew leaf diseases.

   Dr. Jim Ault at the Chicago Botanic Garden came up with this new hybrid of two native perennial species that solves all three of those issues.

   ‘Summer’s Swan Song’ grows only three feet tall, has interlocking branches that help hold it into a compact bush shape, and tested out in Chicago Botanic Garden trials with no disease despite other infected ironweed varieties around it. The variety earned CBG’s highest five-star rating in those trials.

   ‘Summer’s Swan Song’ blooms heavily in purple from September into October and has narrow, olive-green leaves and red-purple stems.

   It’s a popular species with pollinators, but deer don’t like it.

* Size: Including the blooms, plants top out at a little more than three feet tall. Space two- to two-and-a-half-feet apart.

* Where to use: ‘Summer’s Swan Song’ is good for adding late-season color to any mixed garden or perennial border. It’s also a natural for a pollinator garden. Being adaptable to both dry and damp soils, the variety is a good choice for rain gardens, too.

   Full sun is best. Just avoid heavy clay soil.

* Care: Keep damp the first season, then water is usually not needed except in extended dry spells.

   Scatter an organic granular fertilizer formulated for flowers over the bed in early spring.

   Snip off flower stems after bloom, then cut back foliage to the ground at the end of winter. Divide at the same time if clumps are spreading beyond where you want or if you want to move divisions to new areas.

* Great partner: Ornamental grasses such as switchgrass and little bluestem (both U.S. natives) make good textural and fall-interest partners to ironweed. Goldenrod is another native perennial that blooms about the same time and color-contrasts nicely with ironweed’s purple flowers.