Giant Black-Eyed Susans (Rudbeckia grandiflora), also known as rough or tall coneflowers, stand tall in any garden. Large, alternating, gray-green leaves ladder up a tall stalk, which could rise to six feet. The centers of the flowers are also gray-green, but turn brown in a few days.
It ranges as far north as Ontario, south to Texas and Louisiana, and east to Georgia. However, other varieties of Black-Eyed Susans have naturalized fields, pastures, meadowlands and roadsides throughout most of North America, including British Columbia and Newfoundland to the north and Florida and south Texas to the south. The plant has not been very successful in the southwest. Giant Rudbeckia is usually found in warmer zones (7 – 9) but in general, the genus thrives in zones 3 through 9).
Although it is a perennial in many areas, the plant can also be an annual or even a biennial. As a perennial, it is short-lived. Giant Black-Eyed Susans bloom from April through August.
The plant is called a coneflower. But it shouldn’t be mistaken for other plants also known as coneflowers. While all Black-Eyed Susans are of the genus Rudbeckia, other plants are called “coneflowers”, including purple coneflowers (Echinacea), Mexican hat (Ratibida) and clasping coneflower (Dracopsis). However, all are in the Aster family (Asteraceae), and the purple coneflower is closely related to Rudbeckia.
Black-Eyed Susans thrive on sun, and do well in most soils, are drought-tolerant and forgive neglect.
Butterflies, honey bees, beetles and other insects feed on the nectar and pollen of the plant.
Black-Eyed Susans grow well from seed, which germinate in between seven and 30 days, and require little care. Water regularly the first few weeks to establish them and then irregularly afterward.
Black-Eyed Susans look great when planted with purple coneflowers, Russian sage, among vitex and near lilacs. The giant variety is also attractive with cosmos, penstemons, tall cannas and as background accent plants. The plant does very well as a cut flower. It’s a summertime bloomer, and provides flashes of color in a hot weather garden.
There are 25 species of Rudbeckia and all are native to North America. It is named for the Swedish botanist Olaus Rudbeck.
Rudbeckia looks wonderful in gardens, in vases and in open fields. The plant is also known for answering the question: “she loves me, she loves me not,” as lovers pluck petals.
Related articles include:
Growing and Caring for Rudbeckia
Summer Flowering Plants for Hot, Humid Weather
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