Though dispute exists around the taxonomic status of most species within the genus Echinacea the status of E. purpurea is well accepted (Binns et al. 2002).

Echinacea purpurea is a widespread species which occurs throughout much of eastern North America. Like other members of the genus, it grows in tall and mixed grass prairie habitats but is tolerable of a range of soil types and habitats including open forests and glades. It has a long history of medicinal use and remains a popular herbal remedy, despite considerable market volatility. Though habitat loss and collection for herbal markets have put considerable strain on wild populations, cultivated plants now supply the bulk of the medicinal market. Given the historic decline of suitable habitat throughout its range (Samson and Knopf 1994), and the apparent decline of both the size and number of subpopulations in key areas of its range, population declines are evident but the extent and magnitude of these declines is unknown. In addition, as the species is widely cultivated and naturalized, it is not at a significant risk of extinction at this time. Therefore it is considered Least Concern.

Echinacea purpurea is broadly distributed across eastern North America ranging from the Atlantic coast from northern Florida to Connecticut. Its western margin stretches into the plains states and reaches as far west as Iowa, Kansas, and Colorado (USDA, NRCS 2018). The species has been extirpated from the state of Michigan with the last indisputably native population having been observed in the late 1800s (Michigan Natural Features Inventory 2018). It has been introduced in Ontario (VASCAN 2018) among other places, and is widely cultivated within and outside its native range as an ornamental and for industrial production. It is known to easily escape from cultivation and has become naturalized in many places. The species occurs at elevations from 10 to over 400 metres (Flora of North America Editorial Committee 2006).

Though still locally abundant in parts of its range, the species has undergone significant declines and now has a discontinuous distribution with total subpopulations numbering in the hundreds (NatureServe 2019). No systematic surveys documenting population are available, and surveys of the type necessary would be greatly complicated by practices of planting for ornamental purposes. Naturalized populations and remnants from cultivation extend the apparent range of the species well beyond its original extent (Flora of North America Editorial Committee 2006).

Notable declines can be inferred from the failure to relocate stands documented in herbaria within the core of E. purpurea’s range (Applequist et al. 2007). Remaining populations tend to be small, and are likely to be well below the minimum viable population.

Given the historic decline of suitable habitat throughout its range (Samson and Knopf 1994), and the apparent decline of both the size and number of subpopulations in key areas of its range, population declines are evident but the extent and magnitude of these declines is unknown.

Echinacea purpurea occurs in open woodland areas, thickets, riparian areas, and glades in addition to prairie environments (Flora of North America Editorial Committee 2006). The plant forms a spreading, fibrous root system from which several stems may grow (Kindscher 2006a). Stems rise to a height of 1.5 metres from which, a single showy purple cone-shaped flower grows (Lady Bird Johnson Wildflower Center 2019). The species can grow in a variety of soil textures but it requires more water than other members of the genus (Kindscher 2006a). Echinacea purpurea is easily propagated from seed and provides habitat for several species of insects (Lady Bird Johnson Wildflower Center 2019). As with other members of the genus, morphology is highly variable.

Generation length is estimated to be 19 years based on observations of the closely related species E. angustifolia  (Dykstra 2013). Hurlburt (1999) estimates a generation length of 17 – 44 years for E. angustifolia though this estimate reflects considerable environmental variability that likely exceeds that observed within the range of E. purpurea. It is very likely that under the relatively wetter conditions throughout E. purpurea’s range, its development proceeds much more quickly and is perhaps as little as half that of E. angustifolia.

Historic declines of 80-99% of tallgrass prairie ecosystems are documented across the contiguous United States (Samson and Knopf 1994). This has resulted in fragmentation of subpopulations of all Echinacea species, loss of significant tracts of suitable habitat, and population declines (Kindscher 2006b). Increased forest cover in the core of the species’ range also contributes to habitat loss (Applequist et al. 2007). Much of this habitat loss is due to fire suppression within the species’ native range. Rapid loss of relatively open woodland glade habitats has resulted in disproportionately large population declines of E. purpurea relative to other species within the genus (Applequist et al. 2007).

Overgrazing may adversely impact E. purpurea populations, particularly grazing in the spring (Kindscher 2006b). Though the historical impact of harvest of wild populations has had significant impact on populations, it is unclear if the threat continues given the rise in popularity of cultivated E. purpurea and E. pallida. Remaining wild populations are generally located on private property, protected areas, or remote locations and face significantly reduced harvest pressure (NatureServe 2019).

As with other medicinal herbs, E. purpurea has experienced several cycles of popularity (Kindscher 2006b). In the 1990s demand for E. purpurea had outstripped wild collected supply (Li 1998). Widespread cultivation in the US and northern Europe helped to ease the pressures of wild collection, and improvements in techniques have resulted in dramatic declines in wild collection. Increased cultivation coincided with a decrease in popularity greatly easing harvest pressures in the early 2000s (Riggs and Kindscher 2006).

Seeds are commercially available and the plant is commonly grown as an ornamental (Lady Bird Johnson Wildflower Center 2019). The roots of the plant have long been used for medicinal purposes. Ethnographic accounts show usage by the Choctaw and Delaware for treatment of cough, gastrointestinal symptoms, and venereal disease (Moerman 2019).

Products containing various species of Echinacea first gained popularity in the mid 19^th century within the eclectic medical tradition and have remained popular since then in both the United States and much of Europe (particularly Germany) (Riggs and Kindscher 2006). More than 800 products containing Echinacea (primarily E. purpurea) are currently marketed in Germany alone (Drisko 2006). Current formulations include all parts of the plant though the rhizomes are the most commonly used. Preparations of E. purpurea are said to treat a variety of conditions but are most commonly marketed as an immunomodulator.

Though E. purpurea has historically been the most popular source of products containing Echinacea, it has been used interchangeably with E. pallida, and E. angustifolia throughout much of its early history (Flannery 1999). Some change has occurred on this front with E. angustifolia falling out of favour among some herbalists and debate rising regarding which parts of the other species are efficacious.

Commercial scale cultivation of E. purpurea has dramatically reduced the pressures faced by wild populations. Between 2000 and 2010 harvest of cultivated plants dominated American markets, averaging 120,000 kg dried subaerial parts per year. Wild harvested dried herb production was estimated at 4,850 kg per year over the same period (American Herbal Products Association 2012). Root cultivation shows a similar pattern with wild harvests amounting to 2.5% of total root production. As with all estimates of herbal products, reported harvests are likely an underestimate. Since 2002, the market for Echinacea products has been stable or in decline, but it is likely that another surge in popularity will occur at some point in the future (Riggs and Kindscher 2006).

The species is listed as Endangered in Florida (USDA, NRCS 2019). Though not specifically protected through much of its range, the species incidentally occurs in a number of protected areas (Kindscher and Wittenberg 2006). Several seed banks hold E. purpurea seeds including Kew’s Millennium Seed Bank (Board of Trustees, RBG Kew 2018).

Though current trends suggest cultivated E. purpurea is likely to be the predominate source of Echinacea into the future, efforts to increase awareness of the threats to the species could improve population recovery.