Rudbeckia hirta

black-eyed susan, blackeyed susan, common black-eyed susan, brown-eyed susan


Leaf Arrangement


Leaf Attachment


Leaf Type


Leaf Shape

elliptic, lanceolate, ovate

Growth Form


Flower Color


Flower Petals


Flower Month

May - October

Height (meters)

0.3 - 1.0

Milky Sap







annual, biennial, perennial

Growing Season

Warm season

Wetland Class


Prairie Coefficient of Conservatism


Field Characters

Achene with 4 nearly equal facets. Stems and leaves hairy, style branches apically elongate, slenderly subulate. Flowers yellow with red-brown spots basally or in the lower half.

Cultural Information

Rudbeckia hirta prefers good drainage but is frequently found in poor, infertile soils. It grows in soils with a pH range of 4.5-7.5 and can take partial shade but does best in full sun. Seed propagation is easy. Seeds collected in the fall (August to September), when the cones turn grey and loose, can be sown fresh in place or stored and planted in spring. Germination is in 1-2 weeks and the plants bloom the first year from seed. Steffen (1997) recommends cold/moist or cold/dry stratification, possiably to break dormancy induced by long term storage. There are 1,600,000- 2,200,000 seeds/lb and the recommended seeding rate is 2 lbs/acre. When grown in pots allow to dry between waterings as seedlings rot easily. Clumps divided in late winter or early spring should be dusted with a fungacide and the foliage cut back to reduce transpiration (Phillips 1985).

Animal Use

Attracts crescentspot butterflies. Said to attract beneficial or predatatory insects and spiders.

Natural History

A warm-season sunflower that reproduces by seed and underground rhizomes. Its lifespan depends on the site and geographic location. It grows in a wide variety of soils, from Canada to the Gulf of Mexico, on plains and prairies. It can be weedy and is an increaser under grazing. The center raised part of the flower turns black when mature giving this wild flower its common name "black-eyed Susan". The name "hirta" comes from the Latin word "hirtus" meaning covered with fine, short hairs. The Acadian name for all of the yellow coneflowers is "marguerite" (Holmes 1990). Brown-eyed Susan's can be aggressive or weedy in disturbed soil, reseeding readily.


Meadows, pastures, old fields, roadsides, prairies.