Plant potted perennial black-eyed Susans (Rudbeckia) in early fall, which Clemson calls the best time, or in mid-April. Annual types go out after the last frost (Clemson). From seed, sow indoors 5 to 7 weeks before planting out and barely cover it, since light helps it sprout (Johnny's), or sow outdoors in fall or early spring after 3 months of cold (Clemson, Wildflower Center). Give them full sun and well-drained soil. Plants sown in early spring can flower the first summer (NC State).
The classic black-eyed Susan, Rudbeckia hirta, is a North American wildflower that is a biennial or short-lived perennial, so many gardeners grow it as an annual (NC State, Clemson). Longer-lived perennials include orange coneflower (R. fulgida), the parent of 'Goldsturm', which spreads by rhizomes (NC State, Clemson), and brown-eyed Susan (R. triloba), a tall, reseeding plant hardy in zones 3 to 9 (Johnny's) and native across eastern North America (Clemson). Bloom runs from early summer into fall (Clemson, NC State, Wildflower Center). Hardiness depends on the species: NC State lists zones 3a to 8b for R. hirta and 3a to 9b for R. fulgida, and Clemson gives 4 to 9 for the perennial types.
When to plant black-eyed Susans
| Timing | What the sources say |
|---|---|
| Early fall (potted perennial rudbeckias) | Clemson says early fall is the best time to plant perennial Rudbeckia |
| Mid-April or after the last frost (spring planting) | Clemson says perennial rudbeckias can also go in mid-April, and annual types are planted in spring after the last chance of frost. Johnny's transplants R. hirta seedlings outdoors |
| 5 to 7 weeks before planting out (seed indoors) | Johnny's sows R. hirta in cells and covers the seed only very lightly, because light helps germination; sprouts appear in 8 to 14 days at 68 to 72°F |
| Early to mid-fall (seed outdoors) | Clemson and the Wildflower Center sow outdoors in fall, which lets winter chill the seed (GardenPal reading). Johnny's direct-sows R. triloba in fall or early spring |
| Early spring (seed outdoors, after chilling) | Clemson and the Wildflower Center say spring-sown seed needs 3 months of cold stratification at 40°F; Johnny's prechills R. triloba for 30 days |
Use our planting calendar with your frost dates to count back 5 to 7 weeks for indoor sowing. A note on seed depth: Johnny's covers R. hirta very lightly because the seed needs light, while Clemson and the Wildflower Center cover 1/4 to 1/2 inch. Our reading is to follow your seed packet, and to stay on the shallow side indoors.
How to plant black-eyed Susans
| Black-eyed Susan (R. hirta) | Orange coneflower (R. fulgida) | Brown-eyed Susan (R. triloba) | |
|---|---|---|---|
| Life cycle | Biennial or short-lived perennial, often grown as an annual (NC State, Clemson) | Perennial that spreads by rhizomes (NC State) | Hardy in zones 3 to 9; reseeds (Johnny's) |
| Light | Full sun to part shade (NC State); the Wildflower Center says afternoon shade can lengthen bloom | Full sun to part shade (NC State) | Sun to part shade (Johnny's) |
| Soil | Moist, well-drained clay, loam or sand; moderate fertility (NC State) | Moist, well drained (NC State) | Average soil (Johnny's) |
| Height | 2 to 4 ft (NC State); about 3 ft (Wildflower Center) | 2 to 3 ft (NC State) | 48 to 60 in (Johnny's) |
| Spacing | 12 to 18 in (Johnny's) | Clemson lists 'Goldsturm' about 2 ft tall and wide | 18 to 24 in (Johnny's) |
Watering, feeding and deadheading
- Water until established. Black-eyed Susans are drought and heat tolerant once settled (Clemson, NC State). The Wildflower Center says an occasional deep watering in a dry year keeps flowers coming.
- Go easy on fertilizer. Clemson calls them moderate feeders and recommends a soil test; NC State says moderate fertility gives the best flowers and to keep them away from lawn edges, where lawn fertilizer adds too much nitrogen.
- Deadhead for more flowers (Clemson, NC State, Johnny's), but leave some seed heads late in the season for goldfinches and other birds (NC State, Clemson).
- Divide perennials every 3 to 4 years in early spring or fall; Clemson says division is the best way to propagate rudbeckia.
- Cut for the vase. Johnny's harvests R. hirta before the flowers are fully open, and says R. triloba lasts 10 to 14 days in a vase.
Black-eyed Susans in containers
Clemson recommends compact cultivars for containers: 'City Garden' (10 to 12 inches), 'Little Goldstar' (14 to 16 inches) and 'Toto Gold' (12 to 16 inches). Use a free-draining potting mix and water more often than in the ground (GardenPal reasoning).
Fall and winter
- Fall is planting time for potted perennials (Clemson).
- Expect self-sown seedlings. R. hirta reseeds freely (NC State, Clemson), and the Wildflower Center says it can become aggressive in ideal conditions. In a meadow, it advises waiting to mow until seed has matured, 3 to 4 weeks after flowering.
- Leave the rosettes. NC State says R. fulgida keeps a low clump of leaves through winter. Clemson clears dead stems in fall, winter or early spring.
Pests and problems
Clemson lists powdery mildew, leaf spots, stem rots, downy mildew and rusts, made worse by wet leaves and crowding, so space plants and water at the base. It also says plants with distorted flowers from viruses or phytoplasmas should be removed and destroyed. Insects include aphids, caterpillars, Japanese beetles and spider mites (Clemson); NC State adds slugs and snails. Deer resistance is moderate per NC State and high per the Wildflower Center.
Black-eyed Susans around the vegetable garden
Clemson says rudbeckia flowers draw bees, butterflies, hover flies and minute pirate bugs, which prey on pests such as aphids and thrips, so a sunny clump near the vegetables pulls double duty. NC State lists R. hirta as a larval host for the silvery checkerspot butterfly, and the Wildflower Center says it tolerates juglone, so it can grow near black walnuts. They pair well with coneflowers and salvia in a pollinator border; see also flowers that attract beneficial insects. Bee balm is another native pollinator plant for the same sunny edge; see when to plant bee balm.
Frequently asked questions
What is the best time to plant black-eyed Susans?
Clemson says early fall is best for perennial rudbeckias, with mid-April as a second option. Annual types go out after the last frost.
Do black-eyed Susan seeds need cold stratification?
For spring sowing outdoors, Clemson and the Wildflower Center say yes: 3 months at 40°F, or sow in fall instead. Johnny's starts R. hirta indoors without a chilling step.
Do black-eyed Susan seeds need light to germinate?
Johnny's says yes and covers the seed very lightly. Clemson and the Wildflower Center cover it 1/4 to 1/2 inch, so follow your packet.
Will black-eyed Susans bloom the first year?
R. hirta often does when sown in early spring (NC State). Perennial types from seed can take longer; Clemson says seed-grown plants may take 2 years or more to reach a good size.
Do black-eyed Susans come back every year?
R. hirta is short-lived but reseeds (NC State, Clemson). Orange coneflower (R. fulgida) is a true perennial that spreads by rhizomes (NC State).
Are black-eyed Susans deer resistant?
Fairly. NC State rates them moderately deer resistant and the Wildflower Center rates them high.
Enter your frost dates to time indoor black-eyed Susan sowing or a fall planting.
Open itSources
- Virginia Cooperative Extension, "Companion Planting in Gardening" (SPES-620P)
- University of Maryland Extension, "Vegetable Succession and Companion Planting"
- Oregon State University Extension, "Companion Planting"
- Penn State Extension, "Herbs Make Good Plant Partners and Companions"
- University of Minnesota Extension, "Planting the vegetable garden"
- USDA Plant Hardiness Zone Map
- NOAA NCEI U.S. Climate Normals (frost/freeze data)
- Clemson Cooperative Extension HGIC, "Rudbeckia"
- NC State Extension Gardener Plant Toolbox, "Rudbeckia hirta"
- NC State Extension Gardener Plant Toolbox, "Rudbeckia fulgida"
- Lady Bird Johnson Wildflower Center, "Rudbeckia hirta"
- Johnny's Selected Seeds, "Rudbeckia hirta: key growing information"
- Johnny's Selected Seeds, "Rudbeckia triloba: key growing information"
Pairings are summarized in our own words from extension-service guidance. Research support for many companion effects is limited, so treat them as good habits, not guarantees.