Rudbeckia hirta was first described by Linnaeus in 1753 in Species Plantarum. In 1904, O.A. Farwell described the variety pulcherrima in the Annual Report of the Michigan Academy of Science. Then, in 1957, R. Perdue, Jr., published "Synopsis of Rudbeckia Subgenus Rudbeckia" in which the four recognized varieties included hirta, pulcherrima, angustifolia and floridana.
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.
Range and Habitat in Illinois
Regularity: Regularly occurring
Regularity: Regularly occurring
east of the Rocky Mountains [45,51]. It has been sporadically introduced
into the Pacific Northwest . Black-eyed Susan has also been
introduced in Europe as an ornamental and can now be found growing wild
in seminatural stands .
Rudbeckia hirta var. hirta occurs from Pennsylvania to Georgia and
sparingly north to Maine and west to Illinois . Rudbeckia hirta
var. angustifolia is in the South . Rudbeckia hirta var. brittonii
is found in the southeastern United States [48,55]. Rudbeckia hirta
var. floridana is found in central Florida . Rudbeckia hirta var.
pulcherrima is widespread, especially in disturbed habitats .
Regional Distribution in the Western United States
This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):
2 Cascade Mountains
3 Southern Pacific Border
5 Columbia Plateau
8 Northern Rocky Mountains
10 Wyoming Basin
13 Rocky Mountain Piedmont
14 Great Plains
15 Black Hills Uplift
16 Upper Missouri Basin and Broken Lands
Occurrence in North America
KS KY LA ME MD MA MI MN MS MO
MT NE NH NJ NM NY NC ND OH OK
PA SC SD TN TX VT VA WA WV WI
WY AB BC MB NB NF NS ON PQ SK
Rudbeckia hirta spans the entire U.S., except Arizona and Montana, and the southern reaches of Canada. Var. pulcherrima can be found throughout this entire range, but the other varietal populations are localized. Var. floridana is isolated in southern Florida, while var. angustifolia grows through the entire Gulf Coastal plain. Var. hirta is mostly found from the Appalachians to Illinois, but it can be found along the entire U.S. Atlantic coast. (Urbatsch & Cox, 2006.)
For more information, see the map provided by Flora of North America.
Distribution and adaptation
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.
For a current distribution map, please consult the Plant Profile page for this species on the PLANTS Website.
Black-eyed Susan is a native, warm-season, annual, biennial or
short-lived perennial forb [26,34]. It has one to a few stems  12 to
40 inches (0.3-1.0 m) tall , which are erect and sometimes sparingly
branched . The lower leaves are 2 to 6 inches (5-15 cm) long ,
alternate and petioled . The upper leaves are mostly sessile .
The inflorescences are few to many flower heads on peduncles 2 to 8
inches (5-20 cm) long . The fruit is an achene 0.06 inches (1.5 mm)
long; there is no pappus . Black-eyed Susan has a taproot or a
cluster of fibrous roots . It is a mycorrhizal species .
Key taken from Flora of North America. (Urbatsch & Cox, 2006.)
1. Annuals, biennials, or perennials; stems branched at bases or proximal to or
at or near mid heights, leafy mostly toward bases (leaves smaller distally);
peduncles usually at least ½ plant heights (Gulf Coastal Plain, Florida to Texas).
2. Stems branched mostly at or near mid heights; basal leaves oblanceolate,
faces hispid to + sericeous; Georgia to Texas…………………………….
……………………………..……….19a. Rudbeckia hirta var. angustifolia
2. Stems branched at or near bases (plants often scapiform); basal leaves
obovate to nearly orbiculate, faces scabrous to hirsute; c, s Florida……..
…………………………………………19b. Rudbeckia hirta var. floridana
1. Biennials or perennials; stems branched mostly beyond mid heights, leafy +
throughout; peduncles to 1/3 plant heights.
3. Leaves: basal blades broadly ovate to broadly elliptic, 2.5-7 cm wide (lengths
mostly 2 times widths), margins coarsely toothed; cauline (sometimes sessile)
lanceolate, ovate, or pandurate (mostly Appalachian Highlands to Illinois) …….
……………………………………………………19c. Rudbeckia hirta var. hirta
3. Leaves: basal blades lanceolate to oblanceolate, 1-2.5(-5) cm wide (lengths
3-5 times widths), margins entire or serrulate; cauline blades spatulate,
oblanceolate, or broadly linear……… 19d. Rudbeckia hirta var. pulcherrima
"Annuals, biennials, or perennials, to 100 cm (taprooted or roots fibrous). Stems hispid to hirsute (hairs spreading, 1+ mm). Leaves: blades elliptic, lanceolate, or ovate (not lobed), bases attenuate to cuneate, margins entire or serrate, apices acute, faces hispid to hirsute; basal petiolate, blades 8–30 × 0.5–7 cm; cauline petiolate or sessile, blades (sometimes pandurate) 3–20 × 0.4–4 cm. Heads borne singly or (2–5) in loose, corymbiform arrays. Phyllaries to 3 cm (faces hispid to hirsute). Receptacles hemispheric to ovoid; paleae 4–6 mm, apices acute, often attenuate, abaxial tips hirsute to hispid. Ray florets 8–16; laminae (usually uniformly yellow to yellow-orange or with a basal maroon splotch, sometimes mostly maroon) elliptic to oblong or oblanceolate, 15–45 × 5–10 mm, abaxially hispid to hirsute. Discs 12–22 × 10–20 mm. Disc florets 250–500+; corollas proximally yellowish green, distally brown-purple, 3–4.2 mm; style branches ca. 1.5 mm, apices subulate. Cypselae 1.5–2.7 mm; pappi 0."
Rudbeckia hirta and Thelesperma filfolium have very similar flower heads, but can be distinguished by differences in foliage. R. hirta is also commonly confused with its cousin, R. fulgida.
Range and Habitat in Illinois
low to moderate water requirements, and grows in full sun to partial
shade . It is found in plains and open woods [18,19], sunny
roadsides and meadows , sandhills and bogs , and disturbed
Black-eyed Susan occurs at the following elevations:
Elevation (feet) Elevation (meters)
CA 328-3,937 100-1,200 
CO 5,000-9,500 1,524-2,896 [17,33]
WY 8,200 2,500 .
Key Plant Community Associations
In southwest Michigan black-eyed Susan occurs in wet prairie in
association with goldenrods (Solidago spp.), sedges (Carex spp.), Indian
grass (Sorghastrum nutans), marsh fern (Thelypteris palustris),
queen-of-the-prairie (Filipendula rubra), purple meadowrue (Thalictrum
dasycarpum), prairie cordgrass (Spartina pectinata), and cowbane
(Oxypolis pectinata) .
Associates of black-eyed Susan in tallgrass prairie in central Illinois
include leadplant (Amorpha canescens), sawtooth sunflower (Helianthus
grosseserratus), stiff sunflower (Helianthus rigidus), rattlesnake
master (Eryngium yuccifolium), New Jersey tea (Ceanothus americanus),
and flowering spurge (Euphorbia corollata) .
Associates of black-eyed Susan in remnant upland tallgrass prairie in
west-central Missouri include eastern red-cedar (Juniperus virginiana),
dewberry (Rubus flagellaris), chokecherry (Prunus virginiana), buck
brush (Symphoricarpos orbiculatus), leadplant (Amorpha canescens), and
wild snowball (Ceanothus americanus) .
Associates of black-eyed Susan in montane meadow grasslands within the
Rocky Mountain, Sierran, and Madrean montane conifer forests include
bracken fern (Pteridium aquilinum), California false-hellebore (Veratrum
californicum), monkey flower (Mimulus nasutum), mountain brome (Bromus
marginatus), and iris (Iris missouriensis) .
Associates of black-eyed Susan in Sequoia National Park, California, on
sites adjacent to a giant sequoia (Sequoiadendron giganteum) grove
include California wood fern (Dryopteris arguta), beaked hazel (Corylus
cornuta), American trailplant (Adenocaulon bicolor), incense-cedar
(Libocedrus decurrens), bush chinquapin (Chrysolepis sempervirens),
Richardson geranium (Geranium richardsonii), California buckeye
(Aesculus californica), white hedgenettle (Stachys albens), white fir
(Abies concolor), sugar pine (Pinus lambertiana), Sierra gooseberry
(Ribes roezlii), and western cowbane (Oxypolis occidentalis) .
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
K005 Mixed conifer forest
K007 Red fir forest
K012 Douglas-fir forest
K015 Western spruce - fir forest
K017 Black Hills pine forest
K018 Pine - Douglas-fir forest
K023 Juniper - pinyon woodland
K040 Saltbush - greasewood
K066 Wheatgrass - needlegrass
K072 Sea oats prairie
K073 Northern cordgrass prairie
K074 Bluestem prairie
K081 Oak savanna
K082 Mosaic of K074 and K100
K083 Cedar glades
K084 Cross Timbers
K095 Great Lakes pine forest
K096 Northeastern spruce - fir forest
K098 Northern floodplain forest
K099 Maple - basswood forest
K100 Oak - hickory forest
K102 Beech - maple forest
K104 Appalachian oak forest
K106 Northern hardwoods
K107 Northern hardwoods - fir forest
K110 Northeastern oak - pine forest
K111 Oak - hickory - pine forest
K112 Southern mixed forest
This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):
More info for the term: shrub
FRES10 White - red - jack pine
FRES11 Spruce - fir
FRES12 Longleaf - slash pine
FRES13 Loblolly - shortleaf pine
FRES14 Oak - pine
FRES15 Oak - hickory
FRES17 Elm - ash - cottonwood
FRES18 Maple - beech - birch
FRES19 Aspen - birch
FRES21 Ponderosa pine
FRES23 Fir - spruce
FRES30 Desert shrub
FRES35 Pinyon - juniper
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES41 Wet grasslands
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
1 Jack pine
14 Northern pin oak
15 Red pine
19 Gray birch - red maple
20 White pine - northern red oak - red maple
26 Sugar maple - basswood
31 Red spruce - sugar maple - beech
32 Red spruce
33 Red spruce - balsam fir
37 Northern white-cedar
40 Post oak - blackjack oak
42 Bur oak
45 Pitch pine
46 Eastern redcedar
52 White oak - black oak - northern red oak
53 White oak
55 Northern red oak
60 Beech - sugar maple
62 Silver maple - American elm
70 Longleaf pine
71 Longleaf pine - scrub oak
76 Shortleaf pine - oak
78 Virginia pine - oak
80 Loblolly pine - shortleaf pine
83 Longleaf pine - slash pine
84 Slash pine
107 White spruce
110 Black oak
207 Red fir
210 Interior Douglas-fir
220 Rocky Mountain juniper
237 Interior ponderosa pine
239 Pinyon - juniper
251 White spruce - aspen
All varieties of R. hirta can be found in open spaces such as meadows, roadsides and fields, and open woody areas.
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.
Flower-Visiting Insects of Black-Eyed Susan in Illinois
(Bees collect pollen or suck nectar; flies and beetles feed on pollen or suck nectar; other insects suck nectar; observations are from Robertson, Reed, Evans, Graenicher, Moure & Hurd, Petersen, LaBerge, Herms, Grundel & Pavlovic, Krombein et al., Mawdsley, Estes & Thorp, Swengel & Swengel, MacRae, Lisberg & Young, Smith et al., and Grundel et al. as indicated below)
Apidae (Apinae): Apis mellifera sn (Rb, Ev); Apidae (Bombini): Bombus bimaculatus (Pt), Bombus fraternus (Smh), Bombus griseocallis (Re, Smh), Bombus impatiens (Re); Anthophoridae (Ceratinini): Ceratina sp. (Re), Ceratina calcarata (Gnd), Ceratina dupla dupla sn cp fq (Rb, Gr, Ev), Ceratina mikmaqi (Gnd), Ceratina strenua (Gnd); Anthophoridae (Epeolini): Epeolus bifasciatus sn (Gr), Epeolus interruptus sn (Rb), Epeolus minimus sn (Gr), Triepeolus cressonii cressonii sn (Gr), Triepeolus lunatus concolor sn (Rb), Triepeolus simplex sn (Smh); Anthophoridae (Eucerini): Melissodes agilis sn (Gr), Melissodes bimaculata bimaculata (LB), Melissodes boltoniae sn cp fq (Rb), Melissodes communis communis (Smh), Melissodes illata (Gnd), Melissodes subillata (Re, Gnd), Melissodes trinodis sn (Rb, Gr, Re), Svastra aegis (Smh), Svastra obliqua obliqua sn (Rb), Svastra petulca (Smh); Anthophoridae (Nomadini): Epeoloides pilosula sn (Gr), Nomada articulata sn (Rb, Gr), Nomada placida sn (Gr); Anthophoridae (Xylocopini): Xylocopa virginica fq (Smh); Megachilidae (Coelioxini): Coelioxys alternata sn (Re, Gnd), Coelioxys mexicana sn (Smh), Coelioxys octodentata sn (Rb), Coelioxys texana sn (Gr); Megachilidae (Megachilini): Megachile albitarsis (Smh), Megachile brevis brevis sn (Rb), Megachile latimanus sn (Gr, Ev), Megachile mendica (Ev, Smh), Megachile montivaga sn cp (Rb), Megachile parallela parallela sn cp (Rb), Megachile petulans (Smh), Megachile policaris fq (Smh), Megachile pugnata sn cp (Rb, Re, Gnd), Megachile xylocopoides fq (Smh); Megachilidae (Osmiini): Osmia georgica (Smh); Megachilidae (Trypetini): Heriades leavitti sn cp (Rb, Smh)
Halictidae (Doufoureinae): Dufourea marginatus marginatus (MH); Halictidae (Halictinae): Agapostemon sericea sn (Rb), Agapostemon splendens (MH), Agapostemon texanus texanus (Re), Agapostemon virescens sn cp (Rb, Ev, Re), Augochlora pura (Gnd), Augochlorella aurata fq (Smh, Gnd), Augochlorella striata sn cp (Rb, Gr, Re), Halictus confusus sn cp (Gr), Halictus ligatus sn cp fq (Rb, Gr, Re, Smh, Gnd), Halictus rubicundus sn cp (Gr, Ev, Pt, Smh), Halictus sp. (Lasioglossum sp.) sn (Gr), Lasioglossum albipennis sn cp (Gr), Lasioglossum cinctipes sn cp (Gr), Lasioglossum coreopsis cp (Rb), Lasioglossum coriaceus (Ev), Lasioglossum foxii sn cp (Gr), Lasioglossum imitatus sn cp (Gr), Lasioglossum leucozonium (Gnd), Lasioglossum lustrans sn np (ET, Smh), Lasioglossum pectorale sn cp fq (Rb, Gr, Ev, Re, Gnd), Lasioglossum perpunctatus (Re), Lasioglossum pilosus pilosus sn cp (Rb, Gr, Ev, Re), Lasioglossum pruinosus sn (Rb, Re), Lasioglossum rohweri (Re), Lasioglossum subviridatum (Gnd), Lasioglossum tegulare sn (Gr, Smh), Lasioglossum versatus (MH), Lasioglossum vierecki (MH); Colletidae (Colletinae): Colletes eulophi sn cp (Rb), Colletes robertsonii (Smh); Colletidae (Hylaeinae): Hylaeus affinis (Smh); Andrenidae (Andreninae): Andrena fragilis sn (Gr), Andrena helianthiformis (Smh), Andrena miranda (Kr), Andrena peckhami sn cp (Gr), Andrena rudbeckiae sn cp fq icp olg (Rb, Gr, Ev, Re, Kr); Andrenidae (Panurginae): Calliopsis andreniformis sn (Gr), Heterosarus albitarsis sn cp fq icp (Rb, Kr, Gnd), Heterosarus rudbeckiae sn cp fq olg (Rb, Kr)
Sphecidae (Bembicinae): Bembix americana (Gr, Re), Bicyrtes ventralis (Gr, Re), Glenostictia pictifrons (Rb); Sphecidae (Philanthinae): Philanthus bilunatus (Gr), Philanthus gibbosus (Gr); Sphecidae (Sphecinae): Ammophila kennedyi (Gr), Ammophila nigricans fq (Rb), Ammophila pictipennis (Rb), Prionyx thomae (Rb); Vespidae (Eumeninae): Ancistrocerus catskill (Gr), Euodynerus annulatus (Rb), Euodynerus foraminatus (Gr), Stenodynerus anormis (Rb); Braconidae: Agathis longipalpus (Rb)
Stratiomyidae: Anoplodonta nigrirostris sn (Rb), Hedriodiscus binotata (Gr), Hedriodiscus vertebrata (Gr, Re), Odontomyia cincta (Gr), Odontomyia virgo (Gr); Syrphidae: Allograpta obliqua sn (Rb), Copestylum vittatum sn (Rb), Eristalinus aeneus sn (Rb), Eristalis sp. (Re), Eristalis dimidiatus sn (Rb, Gr), Eristalis stipator sn fq (Rb, Re), Eristalis tenax (Gr), Eristalis transversus sn fq (Rb, Gr, Re), Eupeodes americanus (Gr), Helophilus latifrons sn (Rb), Paragus tibialis sn fp (Rb), Sphaerophoria sp. (Re), Sphaerophoria contiqua sn (Rb, Gr), Syritta pipiens sn (Rb, Gr), Syrphus sp. (Re), Toxomerus geminatus (Gr), Toxomerus marginatus sn fq (Rb, Gr, Re), Tropidia mamillata sn (Rb); Empidae: Empis clausa sn (Rb); Tipulidae: Limonia canadensis (Gr); Milichiidae: Eusiphona sp. (Re), Eusiphona mira (Gr); Bombyliidae: Bombylius major sn (Gr), Chrysanthrax sp. (Re), Dolichomyia sp. (Gr), Exoprosopa caliptera (Re), Exoprosopa decora sn (Rb), Exoprosopa fascipennis sn (Rb), Exoprosopa meigenii sn (Rb), Geron calvus (Gr) fq, Lepidophora sp. (Re), Paravilla sp. (Re), Poecilanthrax sp. (Re), Poecilanthrax halcyon (Gr), Poecilognathus punctipennis (Gr), Poecilognathus sulfurea sn (Rb), Pthiria cincta sn fq (Coquillett, MS), Sparnopolius confusus sn (Rb, Gr), Systoechus sp. (Re); Conopidae: Thecophora abbreviata sn (Gr), Zodion fulvifrons sn (Rb, Gr); Tachinidae: Archytas sp. (Re), Archytas analis sn (Rb), Copecrypta ruficauda sn (Rb), Cylindromyia binotata sn (Rb), Cylindromyia carolinae (Gr), Cylindromyia dosiades (Gr), Cylindromyia euchenor sn fq (Rb), Estheria tibialis (Gr), Gymnosoma fuliginosum (Gr), Phyllomya cremides (Gr), Ptilodexia incerta (Re), Spallanzania hesperidarum sn fq (Rb, Gr); Muscidae: Bithoracochaeta leucoprocta sn (Rb); Anthomyiidae: Leucophora siphonina sn; Calliphoridae: Lucilia illustris (Gr); Lauxaniidae: Camptoprosopella vulgaris sn (Rb); Sarcophagidae: Sphixapata trilineata (Gr)
Tephritidae: Paroxyna clathrata sn (Gr)
Nymphalidae: Boloria bellona (Gr), Chlosyne nycteis (Rb), Limenitis archippus (Rb), Phyciodes tharos (Gr), Speyeria cybele (Rb); Lycaenidae: Lycaeides melissa samuelis fq (GP, Hm, Sw), Lycaena hyllus (Rb), Satyrium calanus (Gr), Satyrium edwardsii (Re); Pieridae: Colias sp. (Re), Colias philodice (Rb), Pieris rapae (Rb)
Hesperiidae: Anatrytone logan (Re), Euphyes vestris (Re)
Ctenuchidae: Cisseps fulvicollis (Rb, Re); Gelechiidae: Gelechia sp. (Gr); Noctuidae: Anagrapha falcifera (Rb); Pterophoridae: Geina tenuidactylus (Gr)
Buprestidae: Acmaeodera ornata (McR), Acmaeodera pulchella (Gr), Anthaxia flavimana (McR); Cerambycidae: Typocerus sinuatus sn fp fq (Rb); Chrysomelidae: Diabrotica undecimpunctata fp (Rb); Cleridae: Phyllobaenus pubescens (Mwd), Trichodes apivorus (Gr), Trichodes nutalli (Mwd); Coccinellidae: Coccinella novemnotata (Gr); Curculionidae: Odontocorynus scutellum-album fp (Rb); Meloidae: Epicauta murina fp (Rb), Zontis vittigera (Gr); Mordellidae: Mordellistena cervicalis (LY), Mordellistena rubrilabris (LY)
Lygaeidae: Ligyrocoris sylvestris (Gr); Miridae: Lygus lineolaris (Rb, Gr), Plagiognathus sp. (Gr)
Rudbeckia hirta is associated with a variety of insects. Many species of bees are pollinators, feeding on nectar. Some caterpillars chew on the leaves and Blackberry loopers (moths) feed on the petals. A few species of flies tend to stay close to the flowers, and goldfinches may eat the seeds. R. hirta is especially susceptible to powdery mildew. Cultivars of R. hirta have been hybridized with cultivars of R. Laciniata (Al-Atabee, Mulligan & Power, 1990.), and many of the types commonly used in cultivation are, in fact, hybrids. 'Kelvedon star', 'Gloriosa' and 'Irish eyes' are a few of the more popular cultivars.
Plant Response to Fire
Black-eyed Susan does not respond uniformly to burning. Depending on
season of burning and local conditions, it often establishes
successfully; existing populations may either increase or decrease in
In south-central New York wildfires burned goldenrod (Solidago spp.)-
poverty oatgrass (Danthonia spicata) fields in the springs of 1962,
1963, and 1964. Adjacent burned and unburned areas were measured for
vegetative response 10 to 26 months after the fires. The average
frequency of black-eyed Susan in unburned areas was 29 percent; in
burned areas it was 2 percent .
In southwestern Missouri after a decade of prescribed burning on glade
grasslands black-eyed Susan had decreased in abundance .
Black-eyed Susan seeds were broadcast in the fall of 1988 on sites in
tallgrass oak savanna in northwestern Illinois. Consecutive spring
prescribed fires were conducted in 1989, 1990, and 1991. By the fall of
1991 there were both seedlings and mature plants of black-eyed Susan on
burned sites .
Black-eyed Susan decreased with repeated dormant season prescribed fire
on one test plot in south-central Wisconsin, but increased every year in
another field subjected to the same treatment .
In south-central Wisconsin the Curtis Prairie has had a biennial burning
schedule since 1950, one-third being burned one year and the other
two-thirds the following year. Black-eyed Susan was not present in
1951, but had appeared in small numbers by 1961. An extended growing
season on the burned prairie appears to enhance presence of black-eyed
Susan. During the spring, daytime temperatures are substantially warmer
on the burned than on the unburned prairie, where the litter layer
retards soil warming. The burned surface also cools faster at night.
These effects are most pronounced in May and June 
Black-eyed Susan in tallgrass prairie in eastern Nebraska on silty clay
loam was burned in early May, early July, and mid-September, 1983.
Plots were sampled in the fall of 1983, 1984, and 1986. Burning,
particularly summer and fall burning in years with adequate
precipitation, resulted in higher black-eyed Susan seedling
establishment than occurred without burning. In dry years burning
reduced seedling establishment. Black-eyed Susan cover also increased
with summer and fall burning; cover decreased without burning .
Black-eyed Susan on a poor condition prairie range site in north-central
Oklahoma was burned April 1, 1965-1967, in conditons where the soil was
moist and the fire burned against a 5 to 10 mile-per-hour (8-16 k/h)
breeze. Matched unburned plots were mowed earlier in the spring, and
the residue removed. In the spring of 1966, black-eyed Susan flowered
profusely on unburned plots, but was absent on burned plots .
The Research Project Summary, Herbaceous responses to seasonal burning in
experimental tallgrass prairie plots provides information on postfire response
of black-eyed Susan in experimental prairie plots that was not available when this
species review was originally written.
Immediate Effect of Fire
Black-eyed Susan is probably top-killed by fire during the growing
season. It may survive by sprouting from the root crown .
Initial-offsite colonizer (off-site, initial community)
Caudex, growing points in soil
Black-eyed Susan probably has good fire tolerance in the dormant state,
since it reproduces vegetatively from the root crown [48,56]. It
produces numerous small seeds  and can establish on burned sites.
Black-eyed Susan thrives in the open, sunny conditions [31,51] created
by fire. It may be an initial on-site colonizer since its seeds are
found up to 4 inches (10 cm) or deeper in the seedbank . However,
no information was available on seed tolerance to heat or length of seed
viablility in the seedbank.
More info for the term: succession
Facultative Seral Species
Black-eyed Susan is considered a pioneer species , and can be
dominant in early stages of succession .
Black-eyed Susan is part of the weed stage of abandoned fields in
central Oklahoma and southeastern Kansas .
At the establishment of the Curtis Prairie in south-central Wisconsin
between 1936 and 1941, black-eyed Susan plants were left intact, as they
already occurred in some fields. They persisted a short time, spreading
opportunistically into other areas. Areas originally dominated by
black-eyed Susan were invaded extensively by various more aggressive
In a tallgrass prairie establishment effort in southern Wisconsin, begun
in 1974, black-eyed Susan appeared in 1975, though it had not been
seeded. It was abundant in the surrounding area, however .
Black-eyed Susan reproduces sexually by seed [4,28]. It is pollinated
by bees and flies [15,22]. It also reproduces vegetatively  by
sprouting from the root crown .
In remnant tallgrass prairie in central Illinois, black-eyed Susan seeds
made up 2.4 percent of germinable seeds found in the seedbank. Fifty
percent of black-eyed Susan seeds were in the upper 0.8 inches (2 cm) of
soil; the rest were in the next 3 inches (8 cm) of soil. The seeds
occurred in high-density clumps rather than being randomly dispersed.
Black-eyed Susan was a very minor component of the vegetational cover.
There were more black-eyed Susan seeds in the seedbank than would be
predicted by its importance value .
Black-eyed Susan seed germination varies with area and time of
collection, and with germination conditions.
Black-eyed Susan seeds were collected from wild seed sources in central
Wisconsin in the fall of 1976. The seeds were given cold, dry
stratification for at least 2 months, before germination testing.
Germination ranges were 0 to 38 percent. When grown in soil in 1977,
none germinated; in 1978, germination in soil ranged from 10 to 24
percent. The higher rate in 1978 was probably due to reduction in
dormancy and to higher germination temperatures than in 1977. Light had
no marked effect on the germination of black-eyed Susan seeds in this
study. Wild black-eyed Susan had a very wide range of Pure Live Seed
In a germination study of Wisconsin tallgrass prairie plants, seeds were
collected from the southern tier of Wisconsin counties. With 3 months
cold stratification, black-eyed Susan had a maximum of 46 percent
germination. However, germination values for seeds collected in
different years fluctuated greatly. In some years seeds would germinate
even though unstratified .
In trembling aspen (Populus tremuloides)-dominated vegetation in western
Colorado, black-eyed Susan seeds were collected September 2-3, 1981.
Germination tests were conducted within 6 months of collection.
Germination rates were very low in the absence of light and without
stratification. Germination rates ranged from 24 to 36 percent for
moistened seeds grown in light and stratified 30 to 120 days .
Growth Form (according to Raunkiær Life-form classification)
Life History and Behavior
More info for the term: root crown
Black-eyed Susan is able to flower its first year , but flowers more
prolifically its second year. By the end of the first year it may begin
vegetative reproduction, and show a distinct "bunching" effect with 2 or
more shoots . Topgrowth dies back each year [36,42]. Biennial and
perennial forms sprout the next spring from the root crown .
Black-eyed Susan initiates growth in late spring and becomes dormant by
early fall .
Black-eyed Susan flowering times are:
Begin Peak End
Flowering Flowering Flowering
FL May ---- October 
IL June ---- September 
KS June ---- August 
MI June ---- August 
MN June July July 
MO June ---- August 
NC May ---- July 
ND July July August 
SC May ---- July 
TX June ---- ---- 
WI June ---- August 
Great Plains May ---- September 
Northeast US June ---- October .
Vars. floridana, hirta and pulcherrima can be found in bloom from spring to fall, but var. angustifolia has a shorter flowering period lasting from spring to summer. (Urbatsch & Cox, 2006.) Studies show that several factors including climate warming and day length can induce or delay the flowering cycle. Increasing temperature seems to be correlated with an earlier onset of blooming. (Bradley, Leopold, Ross & Huffaker, 1999.) If day length never increased in the spring, Rudbeckia hirta would never grow beyond its rosette, therefore never producing flowers. (Harkess & Lyons, 1994.)
Annuals, biennials and perennials. Vars. angustifolia and floridana are known to undergo all three life cycles. Var. hirta is biennial or perennial, and var. pulcherrima is annual or perennial. (Urbatsch & Cox, 2006.)
One to several years. Many hybrids have a shortened life cycle, lasting a year or less.
Rudbeckia hirta has a moderate growth rate.
Physiology and Cell Biology
A 2005 study identified three different chromosome types in Rudbeckia hirta, with a chromosome number of 2n=36. Its karyotype is considered to be asymmetric and evolved. (Cimpeanu, M., C. Cimpeanu, Capraru & Costeea, 2005.)
Molecular Biology and Genetics
Although naturally diploid, polyploidy has been exploited in the cultivation of Rudbeckia hirta. The tetraploid cultivar of var. pulcherrima, commonly known as the Gloriosa daisy, has a drastically shortened lifespan as a tradeoff for its almost double-sized flowerheads. (Cullina, 2000.)
Barcode data: Rudbeckia hirta
Statistics of barcoding coverage: Rudbeckia hirta
Public Records: 5
Specimens with Barcodes: 19
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Rudbeckia hirta var. hirta is classified as an endangered plant in the State of New York. (USDA, 2010.)
Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status (e.g. threatened or endangered species, state noxious status, and wetland indicator values).
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.
Legislation of 1918 designated Rudbeckia hirta the state flower of Maryland. Also, the Highway Beautification Act of 1965 has led to a cascade of similar legislations requiring funding for the planting of native wildflowers along highways. This has undoubtedly influenced populations of Rudbeckia hirta and similar native wildflowers.
Black-eyed Susan may be an indicator of range condition. In the western
Cross Timbers of northern Texas on fine sandy loam soil, black-eyed
Susan was not present on range in excellent and good condition, had
coverage of 2 percent on range in fair condition, and had coverage of 4
percent on range in poor condition . The Missouri grass glades were
overgrazed from the late 1800's until the 1960's. By the 1930's on
overgrazed open range the composition of the once productive prairie
glades had changed to a community of soft chess (Bromus mollis) and
black-eyed Susan .
Tallgrass prairie in north-central Oklahoma was subjected to
short-duration grazing schedules from 1985 to 1988. Black-eyed Susan
did not respond to different grazing schedules, but did fluctuate in
numbers in response to environmental conditions influencing its
Black-eyed Susan was grazed by white-tailed deer in southeastern
Minnesota in 1983 and 1984. The grazing did not significantly affect
seedling survival in wet years. However, under drought conditions
grazed plants might not be able to resume growth sufficiently to survive
winter or compete successfully with annuals the following spring .
Herbivory may decrease seed yield from black-eyed Susan. Black-eyed
Susan plants in a pasture in southern Oklahoma were infested with the
silvery checkerspot butterfly (Nymphalidae) caterpillar during the
summer of 1981. Heads from infested plants produced 50 percent fewer
seeds than did heads from uninfested plants. Dispersion of black-eyed
Susan plants may decrease infestation because of the limited distances
the caterpillars can travel .
Fertilization of black-eyed Susan is probably not effective [27,32].
Black-eyed Susan may be extremely sensitive to ozone exposure. More
than 50 percent of black-eyed Susan plants showed foliage injury in
response to the ambiant ozone levels which occurred in the Great Smoky
Mountains in 1989. With ozone exposure twice ambient level, injury was
greater than 90 percent .
Black-eyed Susan may be a good indicator species for soil cadmium. In
northwestern Indiana urban-industrial regions the soil is contaminated
with cadmium and other heavy metals. Black-eyed Susan seed germination
was reduced in proportion to additions of soil cadmium .
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.
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.
Relevance to Humans and Ecosystems
Value for rehabilitation of disturbed sites
Black-eyed Susan is recommended for restoration of disturbed areas and
Black-eyed Susan seeds are available for restoration and conservation
efforts from the USDA Soil Conservation Service Plant Materials Center
at Corning, New York .
Roadside sites: Black-eyed Susan seeds or plants were used along
highways in Wisconsin as part of a natural tallgrass prairie roadside
restoration project. Black-eyed Susan gave excellent response to all
attempted propagation methods: direct seeding on the field site;
transplanting seedlings; and tranplanting year-old plants .
Black-eyed Susan, along with other native wildflowers, was used in
Massachusetts to restore a roadside site that had shallow, infertile
soil, poor moisture retention, and hostile exposure. After 4 years,
black-eyed Susan was one of few survivors at the site .
Black-eyed Susan was used in the rehabilitation of a sand and gravel
borrow-pit in Greene County, Ohio in 1986 and 1987. Black-eyed Susan
was inconspicuous and aboveground growth was slow the first summer, but
during the second year (1987) it flowered. On the drier, less fertile
sites black-eyed Susan flowered in 1988, even though it was still quite
Mine sites: Black-eyed Susan, along with other native prairie forbs and
grasses, was planted on iron mine tailings in west-central Wisconsin.
The tailings are sandy loam in texture, lack essential nutrients, are
very low in organic matter, and have an average pH of 8.5. Seed was
broadcast by hand, raked in, and mulched. No artificial watering or
weeding was done. Of the black-eyed Susan seeds planted, 6.8 percent
produced seedlings. Growth was slow, but by the second growing season,
many of the plants were flowering. Black-eyed Susan showed very little
response to any fertilizer treatment .
Prairie sites: Black-eyed Susan was used as a cover crop to protect
other forb and grass seedlings in a north-central Illinois oldfield
prairie restoration project .
Black-eyed Susan was used in a seeding effort on open upland and drier
southwest-facing slopes around groves and draws of hickories (Carya
spp.) and oaks (Quercus spp.) in degraded tallgrass savanna in northwest
Illinois. In October and November of 1988, seeds were hand broadcast.
By fall, 1991, there were seedlings and mature black-eyed Susan plants
Other uses and values
The leaves of black-eyed Susan are used to make a tea that is said to be
a diuretic, with some cardiac stimulation properties .
The Forest Potawatomis treated colds with a tea prepared from the roots
of black-eyed Susan .
was lightly grazed by cattle during the last half of April, heavily
grazed during May, and lightly grazed during the first half of June. It
was not grazed at any other time .
In southeastern Minnesota white-tailed deer grazed black-eyed Susan
plants which had been transplanted as seedlings into test plots in the
spring of 1983. Thirty-six percent of black-eyed Susan plants were
grazed in 1983, and 8 percent in 1984. No plant was grazed more than
once. Eastern cottontails and thirteen-lined ground squirrels were
observed in the study area, but they did not make use of black-eyed
Rudbeckia hirta is, first and foremost, an attractive flower commonly used in gardening. The Potawatomi use the roots in a tea to treat colds, and the ray flowers in yellow dye. The leaves are gaining notoriety as they contain a stimulant, often used in teas as diuretics.
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.
Rudbeckia hirta, commonly called black-eyed Susan, is a species of flowering plant in the family Asteraceae, native to the Eastern and Central United States. It is one of a number of plants with the common name black-eyed Susan. Other common names for this plant include: brown-eyed Susan, brown Betty, gloriosa daisy, golden Jerusalem, Poorland daisy, yellow daisy, and yellow ox-eye daisy.
The plant also is a traditional Native American medicinal herb in several tribal nations; believed in those cultures to be a remedy, among other things, for colds, flu, infection, swelling and (topically, by poultice) for snake bite (although not all parts of the plant are edible)
Parts of the plant have nutritional value. Other parts are not edible.
It is an upright annual (sometimes biennial or perennial) growing 30–100 cm (12–39 in) tall by 30–45 cm (12–18 in) wide. It has alternate, mostly basal leaves 10–18 cm long, covered by coarse hair, with stout branching stems and daisy-like, composite flowers appearing in late summer and early autumn. In the species, the flowers are up to 10 cm (4 in) in diameter, with yellow ray-florets circling conspicuous brown or black, dome-shaped disc-florets. However, extensive breeding has produced a range of sizes and colours, including oranges, reds and browns.
The genus name honors Olaus Rudbeck, who was a professor of botany at the University of Uppsala in Sweden and was one of Linnaeus's teachers. The specific epithet refers to the trichomes (hairs) occurring on leaves and stems.
There are four varieties:
- Rudbeckia hirta var. angustifolia. Southeastern United States (South Carolina to Texas).
- Rudbeckia hirta var. floridana. Florida, endemic.
- Rudbeckia hirta var. hirta. Northeastern United States (Maine to Alabama).
- Rudbeckia hirta var. pulcherrima. Widespread in most of North America (Newfoundland to British Columbia, south to Alabama and New Mexico; naturalized Washington to California).
R. hirta is widely cultivated in parks and gardens, for summer bedding schemes, borders, containers, wildflower gardens, prairie-style plantings and cut flowers. Numerous cultivars have been developed, of which 'Indian Summer' and 'Toto' have gained the Royal Horticultural Society's Award of Garden Merit. Other popular cultivars include 'Double Gold' and 'Marmalade'.
Gloriosa daisies are tetraploid cultivars having much larger flowers than the species, often doubled or with contrasting markings on the petals. They were first bred by Alfred Blakeslee of Smith College by applying colchicine to R. hirta seeds; Blakeslee's stock was further developed by W. Atlee Burpee and introduced to commerce at the 1957 Philadelphia Flower Show. Gloriosa daisies are generally treated as annuals or short-lived perennials and are typically grown from seed, though there are some named cultivars.
Symbolism and uses
Maryland state flower
- The black-eyed Susan was designated the state flower of Maryland in 1918. In this capacity it is used in gardens and ceremonies to celebrate, memorialize and show affection for the state of Maryland and its people.
- The Preakness Stakes in Baltimore, Maryland has been termed "The Run for the Black-Eyed Susans" because a blanket of chrysanthemums, decorated to look like black-eyed Susans, is traditionally placed around the winner's neck (actual black-eyed Susans are not in season during the Preakness).
Symbol of Justice
- The black-eyed Susan which also traditionally symbolizes “Justice” makes a very nice cut-flower with a vase life up to 10 days.
Butterfly attractant for enhancing gardens
- Butterflies are attracted to Rudbeckia hirta when planted in large color-masses, creating a beautiful spectacle.
Traditional Native American medicinal uses
- The roots but not the seedheads of Rudbeckia hirta can be used much like the related Echinacea purpurea to boost immunity and fight colds, flu and infections.
- It is also an astringent when used in a warm infusion as a wash for sores and swellings.
- The Ojibwa people used it as a poultice for snake bites and to make an infusion for treating colds and worms in children.
- The plant is also diuretic and was used by the Menominee and Potawatomi peoples.
- Juice from the roots has been used as drops for earaches.
- Certain parts of the plant contains anthocyanins a class of antioxidant with several known health benefits.
- As with any wild plant, it is usually recommended to research carefully before consuming as not all parts of the plant may be edible and to avoid mis-identification with other plants that may look similar to the Black eyed Susan.
- It is widely recommended to always consult one's Doctor before taking any medicinal herb.
- With any herb approved by a Doctor for use, it is widely agreed that recommended dosages and preparation procedures should always be followed.
- The species is also known to be toxic to cats when ingested. 
- Dolgopolov, Y. (2004). A collection of confusable phrases: False 'friends' and 'enemies' in idioms and collocations. Coral Springs, FL: Llumina Press
- "MARYLAND AT A GLANCE: STATE SYMBOLS, Maryland State Flower - Black-Eyed Susan", Maryland State Archives, Maryland Manual Online, http://msa.maryland.gov/msa/mdmanual/01glance/html/symbols/flower.html
- Moerman. D, "Native American Ethnobotany", Timber Press. Oregon. 1998 ISBN 0-88192-453-9
- Moerman. D, "Native American Ethnobotany", Timber Press. Oregon. 1998 ISBN 0-88192-453-9
- Floridata: Rudbeckia hirta.
- RHS A-Z encyclopedia of garden plants. United Kingdom: Dorling Kindersley. 2008. p. 1136. ISBN 1405332964.
- Andy's Northern Ontario Wildflowers: Native Meadow Wildflowers. Black-eyed Susan.
- "RHS Plant Selector - Rudbeckia hirta 'Indian Summer'". Retrieved 2 June 2013.
- "RHS Plant Selector - Rudbeckia hirta 'Toto'". Retrieved 2 June 2013.
- Lacy, Allen (July 21, 1988). "Gloriosa, the Eliza Doolittle of Daisies". New York Times. Retrieved 2013-10-22.
- "Fiscal and Policy Notes (HB 345)". Department of Legislative Services - Maryland General Assembly. 2010. Retrieved 2010-03-13.
- "Black Eyes Susan Wildflower".
- Schillo, Rebecca (2011). Cummings, Nina, ed. "Native Landscaping Takes Root in Chicago". In The Field: 13.
- Black-Eyed Susan
- Rudbeckia hirta
- Moerman. D. Native American Ethnobotany Timber Press. Oregon. 1998 ISBN 0-88192-453-9
- "List of plants toxic to cats".
|Wikimedia Commons has media related to Rudbeckia hirta.|
|Wikiversity has bloom time data for Rudbeckia hirta on the Bloom Clock|
- Germplasm Resources Information Network: Rudbeckia hirta
- USDA Plant Profile: Rudbeckia hirta
- Rudbeckia hirta Large format diagnostic photographs
- A Tale of Two Susans non-scholarly essay on the etymology and history
- Knowlton Foote. 2001. Black-eyed Susan (Rudbeckia hirta L.). New York Flora Association. Newsletter Vol. 13.
Names and Taxonomy
hirta L. [28,35]. It is in the sunflower family (Asteraceae).
Recognized varieties are as follows:
R. h. var. hirta
R. h. var. angustifolia (Moore) Perdue [12,55]
R. h. var. brittonii (Small) Fernald [48,55]
R. h. var. floridana (Moore) Perdue [55,61]
R. h. var. pulcherrima Farwell [35,55]
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