Ornamental · Asteraceae
Black-eyed Susan
Rudbeckia hirta
Plant it once in full sun, and this golden daisy seeds itself 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 lights up roadsides and meadows across much of North America. Each flower carries a ring of yellow petals around a dark brown center, the eye that gives the plant its name. It belongs to the aster family and grows fast and easy, which is why it turns up in so many wildflower beds and cut-flower gardens.
Despite the way it spreads, Rudbeckia hirta is short-lived. Most plants 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 a single planting tends to renew itself year after year without any help from you.
Give it sun and decent drainage and it asks for almost nothing else. It shrugs off heat and the odd dry spell once its roots take hold, blooms from early summer well into fall, and feeds birds with its seed heads through winter if you leave the spent flowers standing.
Care
The short version: full sun and average, well-drained soil, with a deep drink every week or so until the plants settle in. Go light on feeding, deadhead through summer to keep the flowers coming, 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 bit of afternoon shade, but the more sun it gets, the more blooms you'll see and the sturdier the stems stand.
Water
Keep the soil evenly moist while plants are getting going, watering every 7 to 10 days when rain falls short. Once the roots are deep, it handles dry spells well. The one thing it won't forgive is soggy, poorly drained ground.
Soil
Almost any well-drained soil suits it, whether clay, loam, or sand, as long as fertility stays modest. A pH from 6.0 to 7.5 covers the full range it likes. Skip the rich, heavy ground, since lean soil gives you better flowers.
Humidity
Ordinary outdoor air is all it needs, so there's no number to chase here. Air movement matters more than moisture, because crowded, still conditions are what invite powdery mildew onto the leaves.
Feeding
This is a plant that does best a little hungry. Feed lightly, if at all, during the growing season, because too much nitrogen trades flowers for leaves. Lean soil and a modest hand bring the best bloom.
Pruning
Deadhead the spent flowers through summer and the plant keeps pushing new ones into fall. When blooming winds down, cut the stems back, or leave the seed heads standing to feed birds and add winter interest.
Size & spacing
Plants reach 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 air moves freely and mildew has a harder time taking hold.
When to plant
Black-eyed Susan runs on the warm season. Start seed indoors in late winter or sow it straight into the bed once frost has passed, and the plants flower from June through September, stretching into fall if you keep up with 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 plant, and most of its troubles show up on the leaves or low on the stems. Catch them early and a quick fix usually settles things. Match what you see below, then act before it spreads.
Stems wilting and collapsing right at the soil line
This is southern blight, a soil fungus that strikes in warm, humid weather and can fell a plant fast. Look for white fungal threads and small tan pellets at the base of the stem. There's no saving an infected plant, so dig it out along with the surrounding soil, fix the drainage, and keep mulch pulled back from the stems.
Fix:
- Remove and destroy infected plants and surrounding soil
- Improve drainage
- Avoid mulch piled against stems
Ragged holes chewed through young leaves
Slugs and snails go after the tender new growth, and they do their worst damage in damp weather. The giveaway is a silvery slime trail near the holes. Pick them off after dark, clear away the debris they hide under, and ring vulnerable seedlings with a barrier or trap.
Fix:
- Hand-pick slugs and snails
- Reduce excess moisture and mulch near crowns
- Use barriers or traps around young plants
Dusty white film spreading across the leaves
This is powdery mildew, a fungus that takes hold late in the season when plants sit crowded and the air goes still. It looks worse than it is and rarely kills the plant. Pull off the worst leaves, give each plant more elbow room, and keep water off the foliage by aiming at the base.
Fix:
- Improve air circulation by spacing plants
- Remove and discard affected foliage
- Water at the base to keep leaves dry
Toxicity
Good news for households with animals: black-eyed Susan is not toxic. It doesn't appear on the ASPCA's poison list, and pets, livestock, and children can be around it safely. The only thing to watch is the bristly foliage, which can leave sensitive skin a little itchy, so reach for gloves when you cut it back.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats Safe
Black-eyed Susan isn't on the ASPCA toxic list, so a curious cat that nibbles a leaf has nothing to fear. At most the coarse, hairy foliage might leave it drooling for a moment.
Dogs Safe
Dogs can sniff and chew the plant without harm. The bristly leaves may scratch a sensitive mouth, but there's no poison to worry about.
Horses Safe
Horses graze around Rudbeckia with no ill effect, and it carries no toxin known to trouble them.
Rabbits Safe
Rabbits can browse the foliage safely. The rough texture is the only thing that puts most of them off.
Livestock Safe
Cattle, goats, and sheep can share a pasture with it without risk, as nothing in the plant is poisonous to them.
Birds Safe
Birds are drawn to the seed heads in fall, and the seeds are a welcome meal rather than a hazard. Leaving the spent flowers standing feeds finches through winter.
People Safe
The plant is harmless to handle, though the stiff, hairy stems and leaves can leave sensitive skin a little itchy. Slip on gloves when you're cutting it back and you'll have no trouble.
The bristly, hairy foliage and stems may cause mild skin irritation in sensitive individuals; wear gloves when handling.
Varieties
Plenty of Rudbeckia selections exist, but a few 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 carries large 5-inch blooms that shade from gold to lemon around an unusual light green cone instead of the typical dark eye.
Indian Summer
Stout stems hold up enormous golden-yellow flowers that reach 6 to 9 inches across.
Rudbeckia fulgida
The orange coneflower is the dependable perennial relative, spreading by rhizomes and surviving zones 3 to 9, where the short-lived R. hirta rarely sticks around.
How to propagate
Black-eyed Susan is among the simplest plants 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 easy way in. Start it indoors 6 to 8 weeks before your last frost, or scatter it straight in the bed once the frost has passed, and an early spring sowing flowers that same year. After that the plants handle the job themselves, dropping seed each fall so new ones come up year after year.
DivisionEasy
Spring or fall for perennial clumps · Re-establishes within one growing season
Division works on the perennial types such as R. fulgida, since the short-lived R. hirta rarely forms a clump worth splitting. Lift and divide an established clump in spring or fall to keep it vigorous, and it settles back in within a single growing season.
Myths
Black-eyed Susan is a true long-lived perennial that comes back reliably for years.
Rudbeckia hirta is really an annual, biennial, or short-lived perennial. The reason it keeps coming back is self-seeding, not a long-lived root, as the parent plants scatter seed and fade while their offspring fill the gap. If you want one that returns from the same crown year after year, plant R. fulgida instead.
Black-eyed Susan is poisonous to dogs and cats.
Rudbeckia doesn't appear anywhere on the ASPCA toxic plant database, and it's treated as non-toxic to pets. The only catch is the bristly foliage, which can leave sensitive skin mildly irritated.