'Challenger' is a selection of Culver's root, the tall eastern North American native that stands in prairies and moist meadow edges with its whorled leaves and slender, upright flower spikes. Where the straight species carries white spikes, 'Challenger' opens in soft lavender-pink, so a drift of it reads as a hazy, pale vertical accent behind lower perennials. The candle-shaped flowers bloom from the bottom of the spike upward through midsummer, which stretches the display over several weeks.
Like the species, it wants rich, evenly moist soil and sun for at least half the day, and it grows slowly in its first season while it builds a deep crown. Established clumps rarely need staking when grown in full sun, and the stiff, narrow spikes hold their shape well into fall. Long-tongued bees, wasps, and butterflies work the flowers heavily, and the seed heads can be left standing for winter structure before cutting stems back in late winter. Divide in early spring every few years if the center thins.
Ecoregions:Northern ForestsEastern Temperate ForestsGreat Plains
Powdery mildew
White or grey powdery coating on leaves - usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.
Grey Field Slug
Deroceras reticulatum →Large irregular holes chewed in leaves, with slime trails on foliage and soil.
Hand-pick at night, set beer traps, or apply iron phosphate bait. Remove debris and mulch where they hide.