Though a fall knockout, plumbago is best planted in the spring. It spreads slowly from rhizomes that need time to get established before winter. The upright stems with woody bases grow to 18 inches. The plant is rated hardy to USDA zone 5 for Front Range gardens.
Leadwort is very shade tolerant, blooming in spots that receive only a couple hours of sunlight daily. It also thrives in full sun. Plants prosper in average soils and require only occasional watering once established.
Try planting leadwort in combination with feather reed grass, tufted hair grass, asters, buff-red flowered sedums, purple coneflower, and yellow, red or lavender-pink mums. This plant also goes well with yellow, late-summer blooming black-eyed Susans and other sunflower relatives.
Adapted from: Colorado State University Cooperative Extension