Ornamental · Asteraceae
Black-eyed Susan
Rudbeckia hirta
Plant it once in full sun, and this golden daisy just keeps seeding itself back every year.
Full sun
Every 7–10 days
USDA 3–8
2–4 ft · 0.6–1.2 m
Overview
You've probably spotted black-eyed Susan already, the bright gold daisy lighting up roadsides and meadows all over North America. Each flower's got a ring of yellow petals wrapped around a dark brown center, and that's the eye it's named for. It's part of the aster family, and since it grows fast and easy, it's no surprise it turns up in so many wildflower beds and cut-flower gardens.
Here's the thing, though: for a plant that spreads so well, Rudbeckia hirta doesn't actually live long. Most of them run as an annual, a biennial, or a brief perennial that fades after a season or two. What keeps a patch going is the seed it drops each fall, so one planting tends to renew itself year after year without you lifting a finger.
Give it sun and halfway decent drainage and it really won't ask for much else. It shrugs off heat and the odd dry spell once the roots dig in, blooms from early summer well into fall, and if you leave the spent flowers standing, it'll feed the birds with its seed heads right through winter.
Care
The short version: full sun and average, well-drained soil, with a deep drink every week or so until the plants get settled. Go easy on the feeding, deadhead through summer to keep the flowers coming, and let it self-seed so next year's sorted.
Light
Black-eyed Susan flowers best in full sun, six or more hours a day. It'll put up with a little afternoon shade, but the more sun it gets, the more blooms you'll see and the sturdier the stems will stand.
Water
Keep the soil evenly moist while the plants are getting going, watering every 7 to 10 days if the rain isn't keeping up. Once the roots run deep, it handles dry spells just fine. The one thing it really won't put up with? Soggy, poorly drained ground.
Soil
Pretty much any well-drained soil works, whether it's clay, loam, or sand, as long as the fertility stays modest. A pH from 6.0 to 7.5 covers everything it likes. Skip the rich, heavy stuff, because lean soil actually gives you better flowers.
Humidity
Plain old outdoor air is all it needs, so there's no number to chase here. What matters more is getting the air to move, since crowded, still conditions are exactly what invites powdery mildew onto the leaves.
Feeding
This is a plant that does better a little hungry. Feed it lightly, if at all, during the growing season, because too much nitrogen trades your flowers for leaves. Lean soil and a light touch get you the best bloom.
Pruning
Deadhead the spent flowers through summer and the plant keeps cranking out new ones into fall. When blooming winds down, you can cut the stems back, or just leave the seed heads standing to feed the birds and add some winter interest.
Size & spacing
Plants get 2 to 4 feet (60 to 120 cm) tall with a spread of 12 to 24 inches (30 to 60 cm). Give each one that much room so the air can move and mildew has a tougher time taking hold.
When to plant
Black-eyed Susan runs on the warm season. Start seed indoors in late winter or sow it right into the bed once the frost's passed, and the plants flower from June through September, stretching 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 customer, and most of its troubles show up on the leaves or down low on the stems. Catch them early and a quick fix usually sorts things out. Just match what you're seeing below, then jump on it before it spreads.
Stems suddenly flopping over down at the soil line
This one's southern blight, a soil fungus that shows up in warm, muggy weather and can take a plant down in a hurry. Check the base of the stem for white threads and tiny tan pellets, and that'll confirm it. There's no rescuing an infected plant, so dig it out with the soil around it, sort out the drainage, and keep the mulch pulled back off the stems.
Fix:
- Remove and destroy infected plants and surrounding soil
- Improve drainage
- Avoid mulch piled against stems
Young leaves chewed up with ragged holes
See a silvery trail near those holes? That's the calling card of slugs and snails, and they love the soft new growth, especially when it's damp out. The fix is hands-on: head out after dark to pick them off, clear away the junk they hide under, and put a barrier or trap around the little seedlings.
Fix:
- Hand-pick slugs and snails
- Reduce excess moisture and mulch near crowns
- Use barriers or traps around young plants
That dusty white film showing up on the leaves
That's powdery mildew, a fungus that likes to move in late in the season when plants are crowded and the air isn't moving. It looks alarming, but it's mostly cosmetic and won't kill the plant. So pluck off the worst leaves, give everything a bit more room, and water at the base to keep the foliage dry.
Fix:
- Improve air circulation by spacing plants
- Remove and discard affected foliage
- Water at the base to keep leaves dry
Toxicity
Got pets at home? Good news, because black-eyed Susan is not toxic. It doesn't show up on the ASPCA's poison list, so pets, livestock, and kids can all be around it safely. The only thing to watch 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
Worried about a nosy cat? Don't be. Black-eyed Susan isn't on the ASPCA toxic list, so a nibbled leaf is no big deal, and the worst you'll get is a bit of drool from those coarse, hairy leaves.
Dogs Safe
Your dog can sniff and chew away at it without any harm done. Sure, the bristly leaves might scratch a tender mouth, but there's no poison here to fret over.
Horses Safe
Horses can graze right around Rudbeckia and be perfectly fine. It just doesn't carry anything that's known to bother them.
Rabbits Safe
Rabbits can munch the foliage with no worries at all. Honestly, the rough texture is usually the only thing that puts them off.
Livestock Safe
Cattle, goats, and sheep can share a pasture with it and stay just fine, since there's nothing poisonous in it for them.
Birds Safe
Birds can't resist the seed heads come fall, and those seeds are a treat, not a threat. Leave the spent flowers standing and you'll keep the finches fed all winter.
People Safe
It's totally fine to handle, though the stiff, hairy stems and leaves can leave sensitive skin a little itchy. Just throw on some gloves when you're cutting it back and you're good to go.
The bristly, hairy foliage and stems may cause mild skin irritation in sensitive individuals; wear gloves when handling.
Varieties
There are loads of Rudbeckia selections out there, but a few really stand out for their size, color, or staying power. These are the ones worth knowing by name.
Prairie Sun
This 2003 All-America Selections winner shows off big 5-inch blooms that go from gold to lemon around a quirky light green cone instead of the usual dark eye.
Indian Summer
Its stout stems hold up huge golden-yellow flowers that get a whopping 6 to 9 inches across.
Rudbeckia fulgida
The orange coneflower is the reliable perennial cousin that spreads by rhizomes and sticks around through zones 3 to 9, while short-lived R. hirta usually doesn't.
How to propagate
Black-eyed Susan is about as easy as it gets to multiply, whether you're growing it from seed or splitting 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 honestly the easiest way to go. Start it indoors 6 to 8 weeks before your last frost, or just scatter it in the bed once the frost's gone, and an early spring sowing will bloom that very same year. And after that? The plants take it from there, dropping seed every fall so new ones pop up year after year.
DivisionEasy
Spring or fall for perennial clumps · Re-establishes within one growing season
Division is really for the perennial types like R. fulgida, because short-lived R. hirta hardly ever makes a clump that's worth splitting. Just lift and divide an established clump in spring or fall to keep it going strong, and it'll settle back in within a single growing season.
Myths
Black-eyed Susan is a true long-lived perennial that comes back reliably for years.
Not quite. Rudbeckia hirta is really an annual, biennial, or short-lived perennial. It keeps coming back because it self-seeds, not because the root lasts, since the parent plants scatter seed and fade out while their seedlings take over. Want one that returns from the same crown every year? Go with R. fulgida instead.
Black-eyed Susan is poisonous to dogs and cats.
Nope. Rudbeckia doesn't show up anywhere on the ASPCA toxic plant database, and it's treated as non-toxic to pets. The only thing to watch is that bristly foliage, which can leave sensitive skin a bit irritated.