Rudbeckia hirta Sahara grown from Farmer Bailey plugs
 
Common Name Rudbeckia
Genus  Rudbeckia
Species hirta, tribola
Family Asteraceae
Life Cycle 
Perennial, or short lived perennial treated as annual.
Tray Size  8
Plug Care Transplant within 2 weeks of arrival.
Netting / Staking No
Temperature Range 25-95F
Spacing 9-12"
Soil Preference Well drained soil of average fertility.
Day Length Obligate long day
Pinching No
When to Plant
In fall, 2-4 weeks before first frost in warmer zones, or in spring around the last frost date.
Harvesting
Cut when flowers are open and stems are stiff. Flowers cut too early may wilt. Keep flowers cut to encourage additional blooms.
Post Harvest Care Holding solution in the cooler.
Diseases / Insects Generally pest free
Bailey's Notes
Rudbeckia hirta can perennialize in some locations, but it generally treated as an annual. They need long days to flower. When planted under short days they will grow roots and leaves and then flower as the days increase in length. Best stem length will come from plants that are established under short days and then allowed to flower as summer progresses. 
Rudbeckia triloba is a true perennial that generally flowers in its first year, but may take an additional season to produce marketable stems.
Resources

NC State Extension Rudbeckia triloba (Brown-Eyed Susan)

USDA Black-Eyed Susan Plant Guide

University of Florida Cooperative Extension Service Rudbeckia Hirta Fact Sheet