Sadly, most of the popular garden favorites have faded by late summer. Yet while daylilies and daisies are no longer blooming, asters and apples won’t appear for at least another month. Luckily, black-eyed Susans stand up to the blazing heat and humidity of August with aplomb, and their bright blooms add some much-needed color to a weary late-summer landscape.
Black-eyed Susans — known officially as Rudbeckia hirta — are easy to grow and don’t need much attention from gardeners once they’re established. Their cheerful, deep yellow petals practically glow in the sun, and their dark centers provide contrast and energy to the familiar daisy shape of these blooms.
Black-Eyed Susan Basics
Growing Zones: 3-7, although they can grow as annuals in colder climates
Bloom Time: Flowers in late summer
Exposure: Full sun
Mature Size: 1 to 3 feet tall and 2 to 3 feet in diameter, depending on the variety
Notes: Black-eyed Susans are native to the Midwestern prairie, so they thrive in hot summers and can withstand drought once established. They also feature rigid stems that hold up in the wind. Their leaves break the soil late in the spring and remain green until they die back at frost. Classic black-eyed Susans have deep brown or black centers and golden, nearly orange petals, although breeders have developed varieties that range from yellow to nearly red.
Growing Black-Eyed Susan in the Landscape
Black-eyed Susans are hardy enough to return year after year in hot, dry parts of your yard, but they aren’t particularly attractive after flowering. They’re a good choice for the middle of a mixed border or as part of a wildflower garden.
To plant your black-eyed susans, dig a hole a bit larger than the pot of your transplant. Black-eyed Susans don’t need exceptionally fertile soil, but they do appreciate some compost added to the hole to help retain moisture as they establish themselves. It’s best to plant these flowers in late spring or early summer, but later plantings may survive the winter with sufficient watering and a late frost. Position the plant at a depth identical to where it was in the pot, and backfill the soil. Press soil firmly in place.
Water your plant deeply and consider adding a layer of compost or bark mulch to hold in moisture. Black-eyed Susans need about an inch of rain per week when getting established and while flowering, so keep an eye on the sky and water every few days if there’s no rain in the forecast. In the following years, they won’t need much irrigation unless you have a severe drought.
It’s also possible to grow black-eyed Susans from seed. Although the plants will be small, they’ll often flower in the first season. You can start them indoors about 6 to 8 weeks before the last frost or sow them directly into your garden 2 weeks before the last frost. Cover seeds with a thin layer of compost and keep moist until they sprout; then, thin so they stand 12-18 inches apart, depending on the variety.
Ongoing Care for Black-Eyed Susan Flowers
After the flowers have faded, you can deadhead them to keep the plant looking neat, and to encourage a secondary bloom. This is optional, though, and many people enjoy the sculptural look of the black seed heads, which will stand tall throughout the autumn and even into winter. Local birds will enjoy the food source as well, and your black-eyed Susans will likely self-sow this way, providing you with additional plants in the spring.
Since black-eyed Susans are native plants, they don’t require additional fertilizer once planted. In fact, too much fertilizer can weaken stems and decrease your flower output. They are also pest-free, making them a truly low-maintenance plant to enjoy for their bright, late-summer color in your garden.