Beautiful black-eyed Susans are the quintessential flowers of summertime. Bright, sunny, and tall, this easy-to-grow summer flower is perfect beside purple cone flowers, daisies, and bee balm.
My mother was always growing black-eyed Susans in her garden, and they still remind me of summer evenings on the front lawn, playing hide and seek with neighborhood kids as the sun sank slowly behind the brick houses that lined our block.
Black-eyed Susans are some of the flowers that make summer memories for me. They’re also pretty hardy and easy to grow. If you’re a busy mom, a grandpa with a green thumb, or a young guy in your first house – black-eyed Susans are among the best flowers for your garden.
All About Black-Eyed Susans
Black-eyed Susans are Rudbeckia genus plants. There are two common species – one an annual, another a perennial. Annual black-eyed Susans are Rudbeckia hirta, while perennial black-eyed Susans are R. fulgida. There is also the biennial brown-eyed Susan (R. triloba).
These are often called orange coneflowers.
Most of the time, if you’re buying black-eyed Susans from the garden aisle of a big store, look closely at the tag. You’ll likely get the annual plant if you buy a packet of wildflower seeds containing black-eyed Susans.
Both species easily reseed themselves, so it can sometimes be hard to know whether you’ve got the annual or perennial in your garden. Hirta are much more common, so it’s a safe bet that you’ve got these.
Even annual black-eyed Susans tend to return year after year thanks to their prolific reseeding. They also both tend to spread and fill out areas of the garden.
Varieties of Black-Eyed Susans
There is an abundance of black-eyed Susan cultivars—annuals, perennials, and biannuals as well as color and size variations.
This pretty biannual produces clusters of small yellow flowers that bloom through late summer and early autumn. Hardy in zones 4-7.
A cultivar of Rudbeckia hirta, ‘Cherry Brandy’ produces deep red or maroon flowers with dark, prominent centers. ‘Cherry Brandy’ is an annual that reseeds well and spreads readily.
‘Goldstrum’ is one of the most popular perennial varieties of black-eyed Susans. This R. fulgida grows about two feet tall on average and produces the quintessential black-eyed Susan bloom in midsummer through early fall. It’s hardy through Zone 4.
This R. hirta makes a delightful annual. It produces a striking, double bloom with two layers of quilled petals. ‘Radiance’ grows only about 18 inches tall, so it’s ideal for mixing in with other lower-growing plants in the middle of the garden.
Or, plant ‘Radiance’ at the back of a lush, low bed of pansies and nasturtiums.
Ideal Locations for Black-Eyed Susans
These sunny flowers love full-sun locations. They do best in garden areas with at least 6-8 hours of sunlight daily. I have seen them do well in partial shade, but they do tend to get leggy – bending and reaching toward the sunlight.
Pick a spot with enough room for the plants to spread. Not only do black-eyed Susans reseed easily, but the perennial plants can also spread underground like mint and monarda. Rudbeckia can really fill in patchy areas in the garden.
These plants aren’t picky when it comes to soil. They’re happy almost everywhere. If you avoid planting them in heavy, wet soil, your black-eyed Susans will settle in and grow happily.
When you pick a location for your Rudbeckia, remember that these flowers will grow tall. Some black-eyed Susans are only about a foot tall, while others grow over five feet in height. Know your variety and plant accordingly.
Most black-eyed Susan plants grow between 2-4 feet tall, making them ideal flowers for the back of the garden bed. Tall black-eyed Susans create a lovely backdrop in the garden. The bright, yellow flowers can help smaller flowers pop.
Starting Black Eyed Susans
You can start perennial black-eyed Susans in the fall or the spring. Annuals should be seeded in the spring. They need enough time to grow, flower, and reseed themselves before the cold weather hits.
Black-eyed Susans can be hardy through USDA Hardiness Zones 3-11, depending on the variety. There’s a Rudbeckia plant for almost everyone.
Whether you’re starting seeds, or transplanting an established Rudbeckia plant, start by preparing the soil. Though black-eyed Susans aren’t picky about soil, it’s always best to start any plant with a little indulgence. Work well-composted manure through your bed, and add a little organic bone meal to boost flowering.
If you’re transplanting, dig a hole just a bit wider but no deeper than the plant’s root ball. Then pop that plant into the hole and fill in around it with both the plant’s old dirt (from the pot) and your new, well-prepared soil.
Make sure the roots are underground, but the base of the stem is uncovered. Then, water well. After transplanting, many people like to mulch the new plant to help maintain soil moisture and deter weeds.
If you’re a mulcher, keep the mulch away from the base of the stem and the leaves, as Rudbeckia like to breathe.
If you’re planting Rudbeckia seeds – whether for annual or perennial black-eyed Susans – wait until the daytime temperatures are consistently around 65-70°F and all danger of frost has passed.
You can also plant them indoors up to 10 weeks before your last expected frost to get a jump on the growing season. For those of us up about Zone 6, starting seeds indoors is a good option.
When seeding in, scatter the seeds over prepared soil and then cover them lightly with soil. Water gently but well. Try to keep the soil moist throughout germination. The seeds should germinate within about 7-21 days, depending on the variety and the weather conditions.
Once your seedlings are established, thin them out to anywhere from 6-30 inches between plants, depending on the variety. Dwarf varieties don’t need as much space as giant varieties.
Depending on when you plant them and the type you’ve chosen, black-eyed Susans usually start blooming in late summer – all through fall until the frost causes them to die back. As part of a cut flower garden, black-eyed Susans are fantastic paired with other tall, long-stemmed, daisy-like flowers and lavender, mums, and ornamental branches.
Black-Eyed Susan Care
Once established, black-eyed Susans don’t need to be watched over or fertilized. Your plants should thrive as long as you weed out around them to maintain airflow and water during droughts.
Tall plants may need to be staked to keep them upright. If you notice your black-eyed Susans drooping, plant a few slender branches or stakes in the ground and gently cage your unruly stems with soft, cotton rope.
If you can, place stakes in a square around the drooping plant and then wrap the rope around all the stakes, creating a soft but supportive cage for the stems to rest on.
Pests and Diseases
Black-eyed Susans are remarkably tough. They have few pests and are a great addition to deer and rabbit-repellent gardens. Occasional aphids are some of the only insects to bother black-eyed Susans, and even these pests will usually choose another host plant over Rudbeckia.
If you see signs of aphids on your plants, spray them with insecticidal soap or neem oil.
In wet weather, black-eyed Susans often get some powdery mildew. But if you maintain airflow between plants and avoid wetting the leaves when you water, you can keep powdery mildew at bay.
If you see signs of powdery mildew, remove the affected leaves and burn them or throw them in the trash.
Overwatered Rubeckia are also inclined to root rot. If you don’t overwater, you’ll usually be safe from root rot unless the weather is exceptionally wet and your soil doesn’t drain well. If your soil is heavy and doesn’t drain well, add some sand to encourage drainage.
Maintaining Black-Eyed Susans
Both annual and perennial varieties of Rudbeckia can spread quickly. Sometimes, you need to divide the plants to encourage healthy growth. If you need to divide your black-eyed Susans, do it in the spring.
Dig up clumps of the plant in early spring. Gently break apart the root mass – use your hands, a fork, or a small shovel. You can also just cut the roots apart. Then, replant the divided flowers with enough space to spread around. Water them well after dividing them.