Rays of Sunshine
The charming black-eyed Susan lights up the garden
In a contest for the most beautiful flower, black-eyed Susan, with its uncomplicated, daisy-like shape, would not win or even be a runner-up. Instead, it would be voted Miss Congeniality. Cheerful, adaptable, and versatile—it would also ace the talent competition—black-eyed Susan is a plant that ticks a lot of boxes. Growing it is a breeze, and the plant looks as much at home in a fancy perennial border as in a meadow. The flowers add that zing of color gardeners yearn for come August. When cut, they last forever in a vase.
Black-eyed Susan is the common name for the 25 species that belong to the genus Rudbeckia. Some species are perennial, others annual or biennial. All are native to North America. Size varies from petite container plants to statuesque seven-foot stunners. They are a low-maintenance clan, easy to grow, and offer a long season of vigorous bloom. Also called brown-eyed Susan or coneflower, do not confuse them with Echinacea, the similar-looking native with purple petals, also known as coneflower.
Who is who in the Rudbeckia family? Well, there is a lot of intermarriage, but the most common black-eyed Susan in gardens is the perennial type, and that is most likely to be ‘Goldsturm’ (R. fulgida var. sullivantii), which is German for gold storm. The most popular Rudbeckia for decades, ‘Goldsturm’ is still readily available, but its disease resistance has declined over time. Also, the cultivar is quite vulnerable to septoria leaf spot, a fungus, and angular leaf spot, a bacterium, which forms black spots on the leaves and is almost impossible to eradicate.
An admirer of ‘Goldsturm’, Allan Armitage, plant researcher and author, most recently of “Armitage’s Greatest Perennials and Annuals” app (available on iTunes), acknowledges that “the diseases are well documented and becoming very problematic. The best substitute is R. fulgida var. deamii,” which is more disease resistant. However, both varieties have received an Award of Garden Merit from the Royal Horticultural Society.
For a black-eyed Susan that does not get lost in a crowd, grow one of the giants. The cutleaf, or green-headed, coneflower (R. laciniata), is a perennial native to New England. ‘Autumn Sun’ has green cones and grows five to seven feet tall, blooming July to September. Great, or cabbage leaf, coneflower (R. maxima) has huge, blue-green leaves with flowers that sway above seven-foot stems. The golden petals draw back against green cones. The foliage is attractive even when there are no flowers.
Two Rudbeckias boast a unique petal shape. The yellow petals of ‘Henry Eilers’ sweet coneflower (R. subtomentosa) are quilled—long and thin—and the plants grow five to six feet high. ‘Little Henry’ is slightly smaller, three to four feet, with the same flowers.
Rudbeckia hirta is the common black-eyed Susan that blooms in fields, ditches, and meadows. It is native to the Midwest but has naturalized in most of the United States and Canada. Many colorful cultivars, named gloriosa daisies, descend from this one. Gloriosas are not always hardy, so treat them as annuals, although they may reseed if conditions are favorable.
Gloriosa daisies come in different heights and sizes and are prized for their glowing colors and floriferous habits. The Toto series tops out at a container-perfect 14 inches, with flowers in russet, lemon, and gold. ‘Autumn Colors’ grows to 22 inches, with orange, russet, and yellow petals and brown cones. ‘Denver Daisy’ has brown cones and yellow-and-brown petals and grows 24 inches high. ‘Prairie Sun’, to 30 inches, and ‘Irish Eyes’, to 36 inches, sport bright green cones and yellow-gold petals. ‘Cherry Brandy’ is a vamp, with sultry red petals and brown cones that reach 20 inches tall.
A new, and still hard to find, Rudbeckia is Echibeckia (R. hirta x E. purpurea), a cross between Rudbeckia and its relative Echinacea. The plants have the fast growth habit, profuse flowering, and colors of Rudbeckia, with the disease resistance and hardiness of Echinacea. Called the Summerina series, the flowers come in brown, yellow, or orange.
Many kinds of Rudbeckia are available in containers at almost every garden center, but growing from seed is not difficult. In fact, many plants self-seed when conditions are right. And those conditions are not too demanding: full sun and soil that is moist and well drained, even sandy. Established plants can handle drought but will always perform best with more moisture. Rudbeckia also accepts light shade, though there will be fewer and smaller flowers. When planting, space plants two to three feet apart, depending on how big the plant gets. In hot, humid climates, give each enough space so that air can circulate, reducing the chance of disease.
Rudbeckia does not need a lot of fertilizer. Too much promotes weak growth and floppy flowers. Topping the bed with a one-inch layer of compost, either in spring or after planting, is enough. Deadhead plants after their initial bloom to keep the flowers coming. Once flowering is finished for the season, leave the plants standing. Birds will eat the seed heads. An exception is if the plants are diseased. Cut those back to the ground and do not compost the debris.
As for where to use black-eyed Susan, you can take her anywhere. Rudbeckia is a natural for meadow or prairie plantings, or a native plant garden. Bees, butterflies, and other insects visit the flowers for pollen and nectar, and finches and chickadees eat the seeds, so it is a vital addition to a garden for wildlife or pollinators. Deer, thankfully, do not particularly care for Rudbeckia, though if food is scarce, all bets are off.
Every cottage garden looks better with a few Rudbeckias, as does any spot where a natural, unstudied look is desired. When used in drifts of five, seven, or nine of the same species, the plants will stop traffic. The shorter gloriosa daisies pop in the front of the border or in containers and are excellent bedding plants when used en masse. Tall R. maxima and R. laciniata are perfect for the back of the border, or use mid-border as “see-through” plants.
“I love using Rudbeckia, both the perennial and annual varieties, for their bold mid- to late-season color,” says Jacquelyn Nooney, landscape designer and principal at JNL Inc. “They mix well with grasses, Sedum ‘Autumn Joy’, and Hydrangea paniculata in a mixed border. Annual varieties like R. hirta ‘Irish Eyes’, ‘Prairie Sun’, and ‘Rustic Color’ are easy to grow from seed and will self-seed if planted where they can be left undisturbed. They look great in the summer garden with other hot colors.”
When it comes to planting partners, you cannot go wrong combining Rudbeckia’s rich golds and yellows with shades of blue or purple. Echo that classic daisy shape with purple coneflower (Echinacea) or any of the asters. Pair its mounding habit with upright growers such as blazing star (Liatris), bee balm (Monarda), sage (Salvia), or hyssop (Agastache). The gold flowers shine even brighter against Russian sage (Perovskia), or with ‘Johnson’s Blue’ geranium at their feet. Ornamental grasses offer a contrast in shape, texture, and color. Little bluestem (Andropogon scoparius), Indiangrass (Sorghastrum nutans), switchgrass (Panicum virgatum), and fountain grass (Pennisetum alopecuroides) all make good companions for Rudbeckia.
Whether you call it black-eyed Susan, brown-eyed Susan, coneflower, or Rudbeckia, the common native with the sunny disposition is an uncommon winner.