Herbaceous Ornamental of the Month: Rudbeckia hirta Hybrids
Posted: June 12, 2012
In 2008, the city of Denver decided to paint their city orange and gold with a new variety of Rudbeckia to commemorate the 150 anniversary of the city. Denver Daisy was developed by crossing the native Rudbeckia hirta with R. ‘Prairie Sun’.
Seeds of the Denver Daisy were distributed to schools, offices, and organizations for the public to grow. This successful campaign beautified the city with six-inch, golden yellow flowers marked with a chocolate brown halo around the central cone. The well-branched plants grow 20 to 26 inches in height with a spread of 10 to 18 inches.
Rudbeckia hirta ‘Cherry Brandy’ is the first-ever red flowering Black-eyed Susan available from seed. The compact plants reach two-feet in height and are smothered with three- to four-inch flowers from summer through fall. The daisy-like flowers are cherry-red intensifying to a deep wine red and punctuated with a black eye.
Unlike older varieties of black-eyed Susan, these new introductions are blanketed with flowers. Another outstanding selection, Rudbeckia ‘Cappuccino’, produces four inch blooms of golden-yellow and copper-red petals surrounding the brown eye.
Throughout the summer, the vibrant flowers attract butterflies and bees, and in late fall and songbirds feast on the seedheads. Rudbeckia are excellent cut flowers and the plants benefit from regular cutting.
These Rudbeckias are relatively maintenance free, standing up to heat, humidity and drought. Deadhead to encourage continued bloom. They are not plagued by insects or disease; however, at the end of a very wet summer in Pittsburgh, a number of varieties exhibited powdery mildew.
While many catalogues state that these species of Rudbeckias are tender perennials, they were not hardy in western Pennsylvania; however, many of the varieties did re-seed.
While many plants do not live up to their marketing campaigns, these Rudbeckias will exceed expectations and provide a spectacular show from summer to frost.