Black-eyed Susan

Rudbeckia hirta (and R. fulgida) · Asteraceae

Tough native wildflower and Maryland's state flower

Photo: G. Edward Johnson, CC BY-SA 3.0, via Wikimedia Commons

Sun: Full sun to part shade
Soil: Average, well-drained soil; adapts to clay and gravelly soils
Soil pH: Adaptable, from acid to alkaline
Water: Moderate until established, then heat- and drought-tolerant
Hardiness: USDA zones 3-9 (varies by species). R. hirta is often short-lived or biennial
Height and spread: 1-3 ft (to 4 ft) x 1-2 ft

Guv's tipDeadhead black-eyed Susans to extend bloom, but leave the late seed heads for the goldfinches. Everyone's happy then.

Through the year

Spring after frost (perennials mid-April), or early fall about six weeks before the first frost

Jun-Oct (start varies from late spring to July)

Deadhead to extend bloom. Leave late seed heads for birds (goldfinches)

Seed (benefits from cold stratification). Readily self-sows

Pest

Look for: Clusters of small soft insects on shoots, sticky honeydew, curled leaves

What to do: Hose off; insecticidal soap or horticultural oil; conserve lady beetles

Disease

Septoria rudbeckiae

Look for: Small dark brown spots 1/8-1/4 in, starting on lower leaves and moving up

What to do: Space plants for air flow, avoid overhead watering, remove debris; preventive fungicide optional (mostly cosmetic)

Disease

Powdery mildew fungi (Erysiphaceae)

Look for: White powdery coating on leaves

What to do: Thin plants for air circulation, avoid overhead watering; low-impact fungicide if severe

Always read and follow the label on any treatment, and check it is approved for use where you live.

Pets and people: Not listed as toxic by the ASPCA, NC State Extension or the University of California toxic plant list

Weed risk: Not on the federal noxious weed list

Checked against two or more reputable gardening sources. How we check our facts

Keep it by the back door

Printable pest and disease charts with real photographs, and all 50 USA plants in one book.