The black-eyed Susan is a botanical traveler that conquered all of North America

Nature · Published 3 October 2026 Swipe more like this →

In short: Known for its iconic yellow petals and dark, dome-shaped center, Rudbeckia hirta is far more than a simple garden staple. From its origins in the eastern and central United States to its status as a naturalized resident across every Canadian province and contiguous American state, this hardy flower holds surprising history.

Rudbeckia hirta, commonly known as the black-eyed Susan, is a member of the Asteraceae family. Its name comes from the Latin word 'hirta', meaning hairy, which describes the coarse trichomes covering its stems and leaves. While the wild species typically grows up to one meter tall with daisy-like flower heads, extensive breeding has produced a vast array of sizes and colors, including deep reds and oranges. The plant is highly adaptable, functioning as an annual, biennial, or perennial depending on its environment.

The plant's cultural footprint is significant. In 1918, it was named the state flower of Maryland, though the famous blanket draped over the winning horse at the Preakness Stakes actually uses chrysanthemums because the real black-eyed Susans are not in bloom during the May race. The flower also inspired the black and gold school colors of the University of Southern Mississippi in 1912, after Florence Burrow Pope observed the blooms in local pine forests. Beyond aesthetics, the plant has a history of medicinal use; the Ojibwa people historically utilized it as a poultice for snake bites and as an infusion to treat colds or worms in children.

Modern horticulture has transformed the species through scientific intervention. In 1957, the 'Gloriosa' daisy—a tetraploid cultivar with significantly larger, often doubled flower heads—was introduced at the Philadelphia Flower Show. These were developed by Alfred Blakeslee, who treated seeds with colchicine, a process later refined by W. Atlee Burpee. Today, the plant serves as a vital ecological anchor, attracting butterflies and acting as a larval host for species like the gorgone checkerspot. While some claim its roots can boost immunity or fight infections, these medicinal benefits remain unsubstantiated, mirroring the traditional uses of its relative, Echinacea purpurea.

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