Master Gardener Ann Bartlett tells a tale of the Rudbeckia clan and Black-Eyed Susan, a fall favorite.
Rudbeckia is a family of flowers native to the eastern United States. Some of the cousins have been domesticated for use in the garden. One of these ornamentals, “Goldsturm,” was the Perennial Plant Association’s plant of the year in 1999. This vigorous plant is popularly known as “brown-eyed Susan.” R. fulgida and R. subtomentosa are both called “black-eyed Susan.”
Go figure!
To my eyes, they are all golden daisies with dark brown centers. The Rudbeckia clan begin blooming in late summer and continue on until frost, making them a great choice for late color in the garden.
Family Members
The Rudbeckia we see blooming by the roadside is most likely R. speciosa, which grows wild from New Jersey to Georgia and Alabama.
There are some spectacularly tall members of the family. R. nitida is about five feet tall and does have some cultivars in the garden trade. They have names like Autumn Sun and Autumn Glory.
R. laciniata is a native that reaches five to ten feet depending on the amount of sun it receives. I got a division three years ago and found that it takes a while to become established. The first two seasons it slept and crept, requiring a good bit of tending. This year it took off and is taller than I am!
How They Grow
These perennials reproduce by rhizomes, forming dense clumps that may be divided every four years. They are tolerant of clay soil but not soggy conditions. Butterflies and pollinators like them. In addition, they are deer-resistant. I guess it would be tough to thrive in our forests if you were a feast for Bambi and his friends!
Another branch of the family is biennial, meaning they produce foliage the first season and flowers the following year. The flowers fade and go to seed and the plant dies. The seeds sprout in a random way, creating a meandering array in the border and working perfectly in cottage-style gardens.
The biennial R. hirta, AKA, “gloriosa daisies," come in a much broader selection of flower forms and colors than the perennial members of the clan. Cherokee Sunset is an All-America Selection featuring many shades of yellow, orange, red, bronze, and mahogany. The gardener may be happier growing this one from seed—both to save money and to enjoy a broader color spectrum.
What color are Susan's eyes?
So, what color are Susan’s eyes? Most are brown, but some, like Prairie Sun, are green. The perennial cousins are foolproof flowers for fall color and look great with both asters and mums.
About the Hamilton County Master Gardeners
Hamilton County Master Gardeners are here to provide you with the latest university research-based gardening information. Whether it’s plant or pest ID, sick plants or general gardening advice, we are here to help!
To reach us, send an email to mghchotline@gmail.com. If you can’t email, call (423) 209-8560 and leave our name, phone number, best time to reach you and a description of your gardening question. If you need help diagnosing a problem, include a few details:
- Damage you see and when it started.
- Parts of the plant affected (for example flower, leaf, stem or fruit).
- How much water the plant gets.
- Plant location (for example in a garden bed or in the lawn, next to a driveway or house, in full or part sun).
- (For emails) Photos of the plant or section of your yard in question. Photos of the area and the entire plant, including closeups, are helpful.