Blackeyed Susan (Hirta)

The Blackeyed Susan (Hirta) is generally described as a perennial forb/herb. This is native to the U.S. (United States) has its most active growth period in the fall and winter and spring . The Blackeyed Susan (Hirta) has green foliage and inconspicuous orange flowers, with an abuncance of conspicuous brown fruits or seeds. The greatest bloom is usually observed in the summer, with fruit and seed production starting in the summer and continuing until summer. Leaves are not retained year to year. The Blackeyed Susan (Hirta) has a short life span relative to most other plant species and a rapid growth rate. At maturity, the typical Blackeyed Susan (Hirta) will reach up to 1 foot high, with a maximum height at 20 years of 0 inches.

The Blackeyed Susan (Hirta) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by seed. It has a moderate ability to spread through seed production and the seedlings have medium vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -23°F. has medium tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Erosion control: Black-eyed Susan is an important component in critical area treatment plantings along with grasses, legumes, and other forbs when used along road cuts, hillsides, and other areas subject to erosion.

Wildlife: This plant offers protection and food to several song and game birds.

Recreation and beautification: Black-eyed Susan can be used for landscaping and in wildflower gardens.

General Characteristics

Rudbeckia hirta L., black-eyed Susan, is a biennial forb about 1 m tall with yellow ray flowers and dark brown spherical centers. After germination, the seedling grows into a rosette with oblong leaves. Sometimes flower stalks will appear in the first summer, but typically black-eyed Susan blooms from June to September of the second year. After flowering and seed maturation, the plants die. The seed is very small (1,746,000 per pound) and black, about 2 mm long and 0.5 mm in diameter.

Required Growing Conditions

Black-eyed Susan is naturalized in most of the states east of Kansas and the bordering areas of Canada. It is adapted throughout the Northeast on soils with a drainage classification range from well-drained to somewhat poorly drained. It will perform acceptably on droughty soils during years with average or above rainfall, but best growth is achieved on sandy, well drained sites. It is winter hardy in areas where low temperatures are between -30 ° and -20 °F.

Cultivation and Care

Black-eyed Susan is easily established with most critical area seeding techniques. Generally ½ lb. of seed per acre is sufficient in mixes with conservation grasses, legumes, and other forbs. Where the intent is to maximize the impact of the forb component, utilize bunchgrasses rather than aggressively spreading grasses such as reed canarygrass or bromegrass. Once established, new seedlings will be produced from the preceding crop; the stand may perpetuate itself indefinitely.

General Upkeep and Control

After establishment, competing perennial vegetation should be controlled through the use of mechanical or chemical practices. If competing vegetation is not controlled, one will observe a decrease in the number of black-eyed Susan plants.

Pests and Potential Problems There are no major insect or disease pests of black-eyed Susan. Stands can be reduced by powdery mildew and damping-off organisms.

Cultivars, Improved, and Selected Materials (and area of origin) 'Golden Jubilee' black-eyed Susan was released by the Big Flats Plant Materials Center in 1985. It is typical of the species except slightly shorter in height with a longer bloom period. It was not selected for its flower size or color. 'Golden Jubilee' is the only cultivar of black-eyed Susan that has proven adaptation throughout the Northeast for conservation use. The original collection area of 'Golden Jubilee' was near Manchester, Vermont. Foundation seed is distributed to commercial producers by the Big Flats PMC in Corning, NY. Black-eyed Susan is readily available from commercial sources.

Plant Basics
Growth Rate Rapid
General Type Forb/herb
Growth Period Fall, Winter, Spring
Growth Duration Annual, Biennial, Perennial
Lifespan Short
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Summer
Displays Fall Colors No
Shape/Growth Form Single Stem
Drought Tolerance Medium
Shade Tolerance Intolerant
Height When Mature 1
Vegetative Spread None
Flower Color Orange
Flower Conspicuousness Yes
Fruit/Seed Abundance High
Fruit/Seed Seasonality Summer Summer
Seed Spread Rate Moderate
Gardening Characteristics
Propagations (Ways to Grow) Seed
Moisture Requirements Medium
Cold Stratification Required No
Minimum Temperature -23
Soil Depth for Roots 10
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Regrowth Rate None
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 6–7 pH
Precipitation Range 28–28 inches/yr
Planting Density 0–0 indiv./acre
Soil Textures Fine, Medium
Soil Depth for Roots 10
Minimum Frost-Free Days 150 day(s)
Salinity Tolerance None
CaCO3 Tolerance None
Sustainability & Use
Leaf Retention No
Palatability Low
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database,
National Plant Data Center, Baton Rouge, LA 70874-4490 USA