Ornamental · Asteraceae
Black-eyed Susan
Rudbeckia hirta
Drop it into full sun once, and this golden daisy seeds itself right back every year.
Full sun
Every 7–10 days
USDA 3–8
2–4 ft · 0.6–1.2 m
Overview
Black-eyed Susan is the bright gold daisy that sets roadsides and meadows alight across much of North America. Every flower fans a ring of yellow petals around a dark brown center, the eye that earns the plant its name. It runs with the aster family and grows fast and easy, which is exactly why it pops up in so many wildflower beds and cut-flower gardens.
For all the ground it covers, Rudbeckia hirta does not stick around long. Most plants run as an annual, a biennial, or a brief perennial that bows out after a season or two. The seed it flings each fall is what keeps a patch rolling, so a single planting renews itself year after year with zero work from you.
Hand it sun and decent drainage and it asks for next to nothing. It powers through heat and the odd dry spell once the roots dig in, fires off blooms from early summer well into fall, and feeds birds with its seed heads through winter whenever you leave the spent flowers standing.
Care
The short version: full sun and average, well-drained soil, plus a deep drink every week or so until the plants dig in. Keep feeding light, deadhead through summer to keep the flowers firing, and let it self-seed for next year.
Light
Black-eyed Susan flowers hardest in full sun, six or more hours a day. It will take a little afternoon shade, but pile on the sun and you get more blooms plus sturdier stems standing tall.
Water
Keep the soil evenly moist while plants get rolling, watering every 7 to 10 days when rain comes up short. Once the roots punch deep, it shrugs off dry spells. The one thing it flat-out refuses is soggy, poorly drained ground.
Soil
Almost any well-drained soil suits it, clay, loam, or sand, as long as fertility stays modest. A pH from 6.0 to 7.5 covers its whole comfort zone. Skip the rich, heavy ground, since lean soil drives better flowers.
Humidity
Plain outdoor air is all it needs, so forget chasing a number here. Keeping the air moving counts for more than moisture, because crowded, still corners are what hand powdery mildew an opening on the leaves.
Feeding
This plant performs best running a little hungry. Feed lightly, if at all, through the growing season, because too much nitrogen swaps your flowers out for leaves. Lean soil and a light hand drive the strongest bloom.
Pruning
Deadhead the spent flowers through summer and the plant keeps cranking out new ones into fall. When blooming eases off, cut the stems back, or leave the seed heads standing to feed birds and add winter interest.
Size & spacing
Plants shoot up 2 to 4 feet (60 to 120 cm) tall with a spread of 12 to 24 inches (30 to 60 cm). Hand each one that much room so air rips through freely and mildew struggles to grab hold.
When to plant
Black-eyed Susan runs on the warm season. Kick seed off indoors in late winter or sow it straight into the bed once frost clears, and the plants flower from June through September, pushing into fall as long as you keep deadheading.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: About 6 to 8 weeks before last spring frost (around March 1 in the St. Louis area)
- Plant: After last spring frost, or direct sow at last frost date
- Harvest: June to September, extending into fall with deadheading
Hardiness
USDA hardiness zones: 3–8
Temperature: down to -40°C
Troubleshooting
This is a tough, hard-charging plant, and most of its troubles surface on the leaves or low on the stems. Catch them early and a quick fix usually shuts them down. Match what you see below, then jump on it before it spreads.
Stems crashing down at the soil line
This is southern blight, a soil fungus that storms in during warm, humid weather and can topple a plant fast. Get down low and check the stem base for white fungal threads and tiny tan pellets to nail the diagnosis. An infected plant is a lost cause, so dig it out with the soil around it, fix the drainage, and keep mulch hauled back off the stems from here on.
Fix:
- Remove and destroy infected plants and surrounding soil
- Improve drainage
- Avoid mulch piled against stems
Young leaves shredded with ragged holes
Slugs and snails are the troublemakers here, zeroing in on soft new growth and chewing hardest when the weather turns damp. Spot a silvery slime trail by the holes and you have caught them red-handed. Head out after dark and pick them off, clear out the debris they hole up in, and ring your seedlings with a barrier or trap to stop them cold.
Fix:
- Hand-pick slugs and snails
- Reduce excess moisture and mulch near crowns
- Use barriers or traps around young plants
A dusty white film creeping across the leaves
Meet powdery mildew, a fungus that sneaks in late in the season once plants crowd together and the air stalls. It looks rougher than it plays, and it almost never finishes a plant off. Strip away the worst leaves, open up real space between plants, and send your water straight to the base so the foliage stays dry and the fungus loses its grip.
Fix:
- Improve air circulation by spacing plants
- Remove and discard affected foliage
- Water at the base to keep leaves dry
Toxicity
Great news for homes with animals: black-eyed Susan is not toxic. It stays off the ASPCA's poison list, so pets, livestock, and kids can all roam around it safely. The only thing to keep an eye on is the bristly foliage, which can leave sensitive skin a little itchy, so grab gloves when you cut it back.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats Safe
Let a curious cat go ahead and nibble, because black-eyed Susan never lands on the ASPCA toxic list. The coarse, hairy foliage might spark a quick bout of drool, and that is the end of the story.
Dogs Safe
A dog can dive in, sniff, and chew with zero harm done. The bristly leaves could scratch a tender mouth, sure, but there is no poison lurking to cause trouble.
Horses Safe
Horses can graze right alongside Rudbeckia and walk away fine, since it packs no toxin known to bother them.
Rabbits Safe
Rabbits can browse the foliage safely whenever they please. The rough texture is the only thing that usually waves most of them off.
Livestock Safe
Cattle, goats, and sheep can graze a pasture full of it without a hitch, because nothing in the plant is poisonous to them.
Birds Safe
Birds zero in on the seed heads come fall, and those seeds make a feast rather than a hazard. Leave the spent flowers standing and you will keep finches fueled all winter long.
People Safe
The plant is friendly to handle, though the stiff, hairy stems and leaves can leave sensitive skin a little itchy. Pull on gloves before you cut it back and you will breeze right through it.
The bristly, hairy foliage and stems may cause mild skin irritation in sensitive individuals; wear gloves when handling.
Varieties
Rudbeckia selections come thick and fast, but a few really break away on size, color, or staying power. These are the ones to know by name.
Prairie Sun
This 2003 All-America Selections winner throws large 5-inch blooms that blaze from gold to lemon around a standout light green cone instead of the usual dark eye.
Indian Summer
Stout stems power up huge golden-yellow flowers that stretch a remarkable 6 to 9 inches across.
Rudbeckia fulgida
The orange coneflower is the rock-solid perennial cousin that marches outward by rhizomes and powers through zones 3 to 9, where short-lived R. hirta rarely hangs on.
How to propagate
Black-eyed Susan ranks among the easiest plants going to multiply, whether you grow it from seed or split an established perennial clump.
SeedEasy
Start indoors about 6 to 8 weeks before last frost, or direct sow at the last spring frost date · Blooms the first year from early spring sowing
Seed is the fast lane into growing this one. Fire it off indoors 6 to 8 weeks before your last frost, or scatter it right into the bed the moment frost clears out, and an early spring sowing rockets to flower that same year. From there the plants run the show, dropping seed every fall so fresh ones spring up year after year.
DivisionEasy
Spring or fall for perennial clumps · Re-establishes within one growing season
Division is the move for the perennial types like R. fulgida, since short-lived R. hirta barely builds a clump worth splitting. Dig up and divide an established clump in spring or fall to charge its vigor back up, and it powers right back in within a single growing season.
Myths
Black-eyed Susan is a true long-lived perennial that comes back reliably for years.
Not so fast: Rudbeckia hirta actually lives as an annual, biennial, or short-lived perennial. It bounces back through self-seeding, not a long-lived root, as the parent plants fling seed and bow out while their seedlings charge in to fill the gap. Crave one that returns from the same crown every single year? Plant R. fulgida instead.
Black-eyed Susan is poisonous to dogs and cats.
Toss that worry out, because Rudbeckia never turns up on the ASPCA toxic plant database and counts as non-toxic to pets. The lone catch is the bristly foliage, which can leave sensitive skin mildly irritated.