This description provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available [8,30,45,54,70].
Purple coneflower is a native, warm season perennial forb that can reach heights of 2.5 feet (76 cm). Seed heads are found on 2 to 5 stems which project 6 to 10 inches (15-25 cm) above the leaves [54]. Purple coneflower supports alternate leaves which are oblong to lance-shaped with 3 to 5 nerves [59]. Basal leaves are 2.0 to 10.6 inches (5-27 cm) in length and 0.4 to 1.6 inches (1-4 cm) wide. Lower cauline leaves are 1.6 to 5.9 inches (4-15 cm) in length and 0.2 to 1.5 inches (0.5-3.8 cm) wide. Upper cauline leaves lack a petiole and are 0.6 to 1.2 inches (1.5-3 cm) high and 0.6 to 1.0 inches (1.5-2.5 cm) wide [70]. Short, stiff hairs encompass both the leaves and stems of purple coneflower [54]. Flowers are 0.8 to 1.6 inches (2-4 cm) long and 0.16 to 0.20 inch (4-5 mm) wide [59].
Plants located in the high plains of Texas and north into Canada are characterized by low heights and flowers that are equal in length or shorter than the width of the disk. As you travel eastward in its range, purple coneflower becomes progressively taller with longer rays [70].
Purple coneflower has a very fragile tap root [7] which is "large" [54] and extends 4.7 to 6.5 feet (1.5-2 m) into the soil [8]. During times of water stress, root growth is emphasized over foliar development and signs of chlorosis may be evident [32]. In a greenhouse study, it was found that purple coneflower responds favorably to the presence of mycorrhizae, experiencing a significant (P≤0.001) increase in mean dry mass weight [111].
Three populations of purple coneflower tested for allelopathic properties in a greenhouse setting displayed adverse effects on 2 potential competitors (switchgrass (Panicum virgatum) and prairie dropseed (Sporobolus heterolepis)) [105]. Further studies are needed to determine allelopathic properties of purple coneflower in a field setting.
Fire adaptations: A study conducted by Wagenius and Shaw [108] found that the percentage of purple coneflower seeds developing into seedlings after a spring burn was 37% that of seeds which were not burned. Other studies have documented the return of purple coneflower populations after prescribed fires [44,73]. Although the ages were not determined, purple coneflower seeds were identified in the top 0.5 in (1.3 cm) of soils after a 7-year drought, suggesting the ability to seed bank [67]. Purple coneflower has been observed sprouting after commercial harvest of the top 6 to 10 inches (15.2-25.4 cm) of root material (Kindscher, personal communication [60]). Whether or not this indicates it can sprout after other types of disturbances, such as fire, is not known. Further research is needed to identify the existence or absence of fire adaptations in purple coneflower.
FIRE REGIMES: The following table provides fire return intervals for plant communities and ecosystems where purple coneflower is important. Find further fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".
Community or Ecosystem Dominant Species Fire Return Interval Range (years) bluestem prairie Andropogon gerardii var. gerardii-Schizachyrium scoparium 61,79] plains grasslands Bouteloua spp. 79,113] blue grama-needle-and-thread grass-western wheatgrass Bouteloua gracilis-Hesperostipa comata-Pascopyrum smithii 79,86,113] blue grama-buffalo grass Bouteloua gracilis-Buchloe dactyloides 79,113] cedar glades Juniperus virginiana 3-22 [46,79] wheatgrass plains grasslands Pascopyrum smithii 79,83,113] interior ponderosa pine* Pinus ponderosa var. scopulorum 2-30 [5,6,66] oak-hickory Quercus-Carya spp. < 35 post oak-blackjack oak Quercus stellata-Q. marilandica 106] little bluestem-grama prairie Schizachyrium scoparium-Bouteloua spp. 79] *fire return interval varies widely; trends in variation are noted in the species reviewPurple coneflower is most often associated with the Great Plains region [2,16]. It grows primarily in open, rocky prairies and plains [45], but also occurs in drainages and depressions [28]. It has been found in scattered and open ponderosa pine stands [102], cedar glades [11], and along fenced roadsides devoid of grazing pressures [33].
Climate: Purple coneflower occurs on mesic sites [28] with average annual precipitation ranging from a low of 15.9 inches (404 mm) in southeastern North Dakota [25] to a high of 40.0 inches (1,016 mm) in central Texas [2]. A gauging station in southeastern North Dakota recorded an average temperature of 41.1 °F (5.1 °C) with low and high temperatures of 6.3 °F (14.3 °C) and 71.2 °F (21.8 °C), respectively [77].
Soils: Purple coneflower tolerates a variety of soil types throughout its range.
State Soil description Kansas alkaline soils [65]Purple coneflower is utilized for forage by both livestock [54] and wildlife [63].
Palatability/nutritional value: Purple coneflower is utilized by livestock and provides nutritious forage where available. In Montana, it is considered a warm season, high-producing plant that is palatable to grazing animals, but subject to population declines under heavy grazing pressures [63]. In Kansas, populations are drastically reduced in grazed areas but continue to do well along fenced roadside borders [33]. On test plots in southern Minnesota, purple coneflower was found to be undesirable as browse for white-tailed deer, eastern cottontails, and ground squirrels [36]. Mature plants are inedible to cattle [89].
Purple coneflower has been successfully added to the feed of undernourished cows and horses in order to stimulate appetite [59].
Cover value: In the Loess Hill prairies of western Iowa, purple coneflower occurs in the prairie-obligate skipper butterfly's habitat [90].
Purple coneflower is found throughout a range of habitat types, predominantly in the Great Plains region.
It is not recognized as a dominant species, but can be found with the following associates:
Grasses: Purple coneflower is frequently associated with the following graminoid species: little bluestem
(Schizachyrium scoparium), big bluestem (Andropogon gerardii var. gerardii),
indiangrass (Sorghastrum nutans), Kentucky bluegrass (Poa pratensis), blue grama (Bouteloua gracilis),
sideoats grama (B. curtipendula), needle-and-thread grass (Hesperostipa comata), and
western wheatgrass (Pascopyrum smithii) [2,4,11,17,18,19,21,23,28,32,39,48,67,69,73,75,77,80,81,85,89,98,100,102,104,114].
Shrubs and forbs: In Nebraska, species commonly found with purple coneflower include flowering spurge
(Euphorbia corollata), downy phlox (Phlox pilosa), wholeleaf rosinweed (Silphium integrifolium),
and white prairieclover (Dalea candida) [17]. In Kansas, it can be found alongside prairie bundleflower
(Desmanthus illinoensis), compassplant (S. laciniatum) [33], dotted blazing star
(Liatris punctata), and desert princesplume (Stanleya pinnata) [65]. In
North Dakota, it occurs with western snowberry (Symphoricarpos occidentalis),
heath aster (Aster ericoides var. ericoides), Louisiana sagewort (Artemisia ludoviciana) [28],
western yarrow (Achillea millefolium), sagewort wormwood (Artemisia campestris), and scarlet beeblossom
(Gaura coccinea) [16].
Trees: Purple coneflower has been observed in scattered and open interior
ponderosa pine (Pinus ponderosa var. scopulorum)
stands in Nebraska [102] and sand shinnery oak (Quercus havardii)
communities in Oklahoma [18]. In Illinois, purple coneflower was present
near a forest of post oak (Q. stellata), chinquapin oak (Q.
muehlenbergii), and eastern redcedar (Juniperus virginiana),
populating the area after tree removal and prescribed fire [73].
Biological:
Wild and commercially-grown populations of purple coneflower are subject to interference from
nonnative plants and a variety of diseases. Wild populations in the oak savannahs of southeastern
Kansas were reduced after an invasion of sericea lespedeza (Lespedeza cuneata) [34]. In
Theodore Roosevelt National Park in southwestern North Dakota, purple coneflower was eliminated
by an infestation of leafy spurge (Euphorbia esula) [24]. In Alberta, commercial populations
have been infested with aster yellows [26], sclerotinia blight (Sclerotinia sclerotiorum)
[109], sclerotinia stem rot and botrytis blight [27].
Extracts from purple coneflower plants have been used to manage populations of both grain beetles
[74] and yellow mealworms [53].
Pale echinacea (Echinacea pallida) has been shown to be highly aggressive
and can outcompete purple coneflower whose dry weight and leaf area are considerably less [96].
Commercial Harvest:
There are potential harvesting pressures on natural stocks of purple coneflower with renewed
interest in its use as a medicinal plant [59]. Commercial production of purple coneflower is
discussed in [7,20,29,50,52,82,110].
Medicinal: Various Native American tribes harvest purple coneflower for a wide range of applications. It is often used in the treatment of snakebite wounds [3,37,40,54,59,87] in addition to oral ailments [37,40,54,59] and various infections [35]. Purple coneflower has both antibiotic and antiviral attributes [1] and can be used to augment immune systems [74].
Given the chemical heterogeneity and lack of standardized procedures for preparation, health care researchers have found it difficult to assess the effectiveness of purple coneflower [71]. Adverse effects stemming from the use of various Echinacea species have been reported to the US Food and Drug Administration [101], and the importance of standardizing preparation methods has been addressed [12].
Earliest first bloom
Latest first bloom
Median date of full flowering
Median date when 95% of flowering complete
Length of flowering period (days)
June 20th
July 12th
July 11th
August 2nd
27
Purple coneflower was thought to reproduce exclusively by seed [10]; however, 15-25% of plants will sprout after removal of the top 6 to 8 inches (15.2-20.3 cm) of root material during cultivation (Kindscher, personal communication [60]).
Breeding system: No additional information is available on this topic.
Pollination: Purple coneflower is pollinated by insects [9]. Availability of pollen is determined by population size. Isolated plants experience greater pollen limitation [107].
Seed production: Purple coneflower relies on seed production to regenerate [76]. Plants begin to produce seed after 1 year of growth [29], with seed yield correlated to pollen availability [107]. In Kansas purple coneflower was the only forb that continued to produce seed in the 3 years following a 7-year drought [22].
Seed dispersal: Purple coneflower disperses its seed gradually from early fall to early summer [32]. Due to the lack of any specialized mechanism for seed dispersal, it is improbable that purple coneflower would colonize habitats distant from a seed source [76].
Seed banking: In a study intended to determine regeneration of plants after 7 years of drought in Hays, Kansas, viable purple coneflower seeds were found in the top 0.5 in (1.3 cm) of soil [67].
Germination: Purple coneflower seeds germinate on the surface of warm, moist soils at temperatures of 68 °F (20 °C) and above during spring months [32] before they are fully afterripened [10]. The seed has a corky covering that, when removed, allows for increased rates of germination. Thirteen percent of seeds with the covering germinated in 5 to 11 days and 92% of seeds without the covering germinated in 2 to 9 days [97].
Purple coneflower's need for stratification is unclear. In a study conducted by Baskin and others [10], 12 weeks of cold stratification were considered essential for seeds to overcome dormancy. In a separate study, it was determined that purple coneflower had low germination rates that were not improved by stratification or presowing treatments [93]. In Montana, purple coneflower seeds 3 months to 3 years of age germinated in high numbers regardless of stratification [32]. By placing seeds on a moist filter paper substrate in the dark and setting a constant temperature of 70 °F (21 °C), Owens and Call [78] observed a germination rate of 92% in 9 days for purple coneflower. When subjected to various thermoperiods and light/dark conditions, purple coneflower seeds displayed a variety of germination rates [10]. By allowing germination to occur in a greenhouse with the use of light, Smith-Jochum and Albrecht [95] found an increase in rates when compared with field germination.
Various treatments have exhibited positive effects on germination rates of purple coneflower. Gao and others found that treating seeds with 5.3M of KOH for 10 minutes increased germination from 30% to 90% and emergence from 12% to 90% [42]. Seeds treated with 1.0 mM of ethephon solution and kept under constant light showed a 29% increase in germination rates. Untreated seeds germinated at a rate of 50% to 60% [88].
Seedling establishment/growth: In a study conducted on 1,249 purple coneflower seedlings, population fragmentation was a significant indicator of seedling vigor [107]. One hundred percent of purple coneflower seeds collected in South Dakota were found to be viable and 76.5% developed mature embryos [97].
Asexual regeneration: While Bare [8] and Umbanhowar [104] maintain that purple coneflower is rhizomatous, Kindscher suggests that it is a tap-rooted species devoid of rhizomes (Kindscher, personal communication [60]). Kaul was also not able to detect any rhizomes on purple coneflower (Kaul, personal communication [58]). Further research may be necessary to verify the existence or absence of rhizomes in purple coneflower.
Purple coneflower can be propagated through cuttings from the thick taproot [47]. Mass propagation can be done using axillary bud proliferation, adventitious shoot formation and somatic embryogenesis [64], potentially producing plants on a scale suitable for commercial needs.
The currently accepted scientific name for purple coneflower is Echinacea angustifolia
DC (Asteraceae) [8,30,45,55]. There are 2 recognized varieties:
E. a. var. angustifolia
E. a. var. strigosa (R.L. McGreg) [45,55]
Throughout this review, purple coneflower will refer to both varieties, E. a. var.
angustifolia and E. a. var. strigosa. The literature does not differentiate between
the 2 infrataxa, so distinction between the varieties will only be made in the distribution and
occurrence section.
Hybrids: In an experimental garden setting, E. a. var. angustifolia
was successfully crossed with eastern purple coneflower (E. purpurea) [70].
Purple coneflower is valuable for the restoration of prairies in the Great Plains region. In central Texas, container grown transplants were a successful part of the Blackland Prairie restoration effort [2]. At the Heard Museum in eastern Texas, strips of sod transplanted from a nearby area and supporting a similar composition of species displayed an initial decrease and subsequent increase in cover and frequency of purple coneflower [98]. In Kansas, purple coneflower plants were grown in a greenhouse and inoculated with Rhizobium bacteria before being transplanted. Two seedlings planted in 1984 survived year 1, and 1 survived the 2nd year, while 88% of 64 seedlings planted in 1985 survived [81]. In Nebraska, individual purple coneflower plants and tallgrass prairie sod were successfully relocated onto restoration sites [19].
Coal mine spoil materials in North Dakota have been successfully seeded with purple coneflower [15,16]. In a 2-year study conducted in southwestern North Dakota, directly seeded forbs, including purple coneflower, produced numerous seedlings in June following original planting [16]. In a separate study conducted in the northern Great Plains region, purple coneflower grown in greenhouse containers produced only a few seedlings after being transplanted, but displayed "exceptional" establishment characteristics and hearty growth in both years [15].
In South Dakota, artificially constructed earthen mounds on low, middle, and high productivity gradients were monitored to determine species richness and yield on a spatial scale. Purple coneflower was found on greater than 35% of the mounds located in each topographic gradient, indicating its ability to respond to disturbances and recolonize sites in which soil degradation has occurred [104].
Eddleman [31] discusses the viability of purple coneflower seeds for reclamation in southeastern Montana. Age of seed, temperatures, stratification, and planting seasons are addressed as factors in success rates. Albrecht and Smith-Jochum [1] discuss methods used in germination and establishment of purple coneflower, including raised beds, soil pH, light availability, precipitation and temperature.
