Floridata: Rudbeckia hirta

#766 Rudbeckia hirta
Common Names: black-eyed Susan, gloriosa daisy, yellow oxeye daisy
Family: Asteraceae/Compositae (aster/daisy Family)

Get link to this Profile or click for Datasheet

Wallpaper Gallery (4 images)

This spectacularly radiant gloriosa daisy is Rudbeckia hirta 'Indian Summer'.

Description
Everyone's favorite summertime flower is the black-eyed Susan, sometimes an annual, sometimes a perennial, and sometimes a biennial (flowering in its second year, then dying). This is a member of the huge aster or composite family, and has the typical daisylike flowerheads consisting of an outer ring of ray florets and a central receptacle composed of many disk florets. Black-eyed Susans typically stay in a basal rosette their first year, and then produce upright branching stems with flowers in their second year. The rough-textured basal leaves are diamond shaped, 4-7 in (10-18 cm) long, and have three conspicuous veins. When she's ready, black-eyed Susan produces erect, bristly stems to 3 ft (0.9 m) tall, which branch freely and bear hairy lance shaped leaves, 2-3 in (5-7.6 cm) long.

Black-eyed Susan is easy and carefree and more than happy to live out on her own by the road under the mailbox.

Some forms of black-eyed Susan are true annuals and some are true perennials, though. The flowerheads in the wild form are up to 3 in (7.6 cm) across and produced abundantly throughout the summer until midautumn. The 10-20 rays are usually yellow or golden and the receptacle is purplish brown and often distinctly conical. There are many garden cultivars. 'Supurba' has ray flowers that are yellow on top and maroon beneath. 'Bambi' is small, to 12 in (30.5 cm), with chestnut colored ray flowers. 'Irish Eyes' has bright yellow rays and green disks. 'Toto' is dwarf and very compact, to 10 in (25 cm) tall, and ideal for edging or containers. The 'Gloriosa' and 'Double Gloriosa' cultivars have very large flowerheads, to 6 in (15 cm) across, with yellow, gold, chestnut or bronze rays. They are perennial, but bloom from seed in their first year. 'Gloriosa' daisies are tetraploids, with twice the normal number of chromosomes. They were created by treating normal plants with radiation or the DNA altering chemical, colchicine. Nevertheless, they come true from seed. 'Indian Summer', with golden yellow flowerheads 6-8 in (15-20 cm) across, and 'Goldilocks', with double flowers are probably tetraploids as well.

Download a large version (800x600) and invite black-eyed Susan to your desktop.

Location
There are three regional varieties of Rudbeckia hirta, the wild black-eyed Susan, with one occurring naturally throughout much of North America from British Columbia to Newfoundland and south to Texas and Florida. The species is absent only from the Southwest. Black-eyes Susans grow in prairies, dry fields, open woods, along road shoulders and in disturbed areas.

Culture
Deadhead spent flowers to prolong blooming.
Light: Full sun to light shade.
Moisture: Once established, black-eyed Susans are fairly drought tolerant, but they perform best with regular watering in soil that does not completely dry out.
Hardiness: USDA Zones 3 - 10.
Propagation: Sow seeds in place 2 weeks before the last expected frost or give them a head start indoors 6-8 weeks before setting out. The seeds need light to germinate, so just press them into the soil surface - don't bury them. Some of the cultivars are decidedly perennial, and these are best propagated by dividing the root mass during the dormant season.

Black-eyed Susan growing among bananas, cannas and elephant ears at the Cincinnati Zoo and Botanical Garden.

Usage
Black-eyed Susan is at home in the naturalized, semi-wild garden, in borders and in flower beds. She won't complain if relegated to the cutting garden, either. Black-eyed Susan is a reliable summertime bloomer, providing bright splashes of color in a mixed perennial border or porch planter. Butterflies of many species are attracted to black-eyed Susan. But one of Susan's most influential uses is for resolving that age old lover's question: "... she loves me, she loves me not, she loves me, she loves me not, she loves me."

Features
There are about 25 species of Rudbeckia, all native to North America. Orange coneflower (R. fulgida var. sullivantii) is another popular garden perennial. Purple coneflower (Echinacea purpurea) is closely related. The genus was named for the Swedish physician/botanist, Olaus Rudbeck (1660-1740), who preceded Carolus Linnaeus, the inventor of the binomial system of biological nomenclature, at the University of Upsala.

Steve Christman 8/18/00; updated 8/15/03, 6/17/04, 3/21/08

Copyright 1996 - 2010 Floridata.com LC Tallahassee, Florida USA

Latest Entries:

Recent Plant Profiles:

New!
Use Floridata's Local Guides to find businesses and learn of community events in your area.

Local Guides

Local Guides
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
DC
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennesee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming