Taenidia integerrima aka Golden Alexander

Taenidia integerrima also goes by the name yellow pimpernel. It belongs to the carrot family, Apiaceae. This herb comes back each year. It is native to southeastern Canada and central and eastern America. Its range runs from Quebec and Ontario west to Minnesota. It reaches south to Georgia and Texas. It grows on rocky slopes, hillsides, and bluff ledges. It also grows in open woods, thickets, and prairies. It is native to the Midwest, but not Britain or Ireland.

The plant grows upright to about 3 feet [0.91 metres] tall. Its spread at full size is about 2.5 feet [0.76 metres]. Its smooth stems range from green to reddish brown. They have a glaucous surface, which means a waxy coat. The leaves split into dull green leaflets with smooth edges. Lower leaves have long stalks and split twice or three times. They bear groups of three to five leaflets. These leaves reach 1 foot [0.30 metres] long. They can reach 0.5 feet [0.15 metres] wide. Upper leaves split once or twice, with leaflets in threes.

The yellow flowers form showy groups called umbels. In each umbel, flower stalks spread from one point. Missouri Botanical Garden gives May through July as the bloom season. Chicago Botanic Garden gives May through August for the blooms. So the show can last from late spring into summer. The blooms draw butterflies to the plant. The sources give no facts about the fruit. They give no evidence about parts to eat or toxic effects.

Part shade and dry soil suit this plant best. It grows in full sun and takes almost full shade. Missouri Botanical Garden says it grows well in peaty woodland soil. Once plants take root, they cope well with drought. Chicago Botanic Garden gives USDA hardiness zones 4–8. Its taste for dry soil suits it to some woodland sites. It is easy to grow more plants from seed.

Yellow pimpernel suits woodland gardens and those for native plants. Chicago Botanic Garden suggests borders and bedding, too. It also suggests planting it beneath trees or shrubs. The upright form and yellow umbels give the main garden interest. Yet few people grow this plant. Missouri Botanical Garden lists no serious pests or diseases. It says the plant needs a medium level of care. This is despite its view that the plant grows with ease.