Purple Coneflower [Echinacea purpurea (L.) Moench] 

botanical information

Echinacea purpurea (L.) Moench is an herbaceous perennial and a member of the Asteraceae family.  Commonly called purple coneflower, it has a natural range extending from Michigan, Ohio, Illinois, Iowa, to southeastern United States and west to Texas.  E. purpurea grows at a rate of twelve to eighteen inches a year to a mature height of two to four feet.  The leaves are ovate to lanceolate and the flowers are cone-shaped disks adorned with deep pink to purple ray flowers that are horizontally spreading.  Flowers bloom from June to August.  Of the three strains used for medicinal purposes (E. purpurea, E. angustifolia, and E. pallida), E. purpurea is the hardiest, with the ability to withstand large temperature and soil moisture variations in its habitat.  Unlike E. angustifolia and E. pallida which possess a taproot system, E. purpurea has a fibrous root system.  The root is harvested three-to-four years from seed.

 E. purpurea is known for its medicinal qualities and is used extensively as an ornamental in the landscape.  It is a well-known fact that echinacea flowers attract a variety of butterflies and bees to the garden.   

medicinal uses

E. purpurea has a long, well-established tradition of medicinal use in North America and Europe.  In modern cultures, it is believed to stimulate the immune system preventing colds and flu.  In Europe, E. purpurea is the most widely accepted species of echinacea used for medicinal purposes.  It is also used in treating urinary tract infections and burns. 

selecting a planting site

E. purpurea can be grown almost anywhere within the temperate zones and is being cultivated in most of these areas.  Echinacea prefers a well-drained alkaline soil in a sunny location.  Recommendations for pH range from 6.0 to 7.5.  E. purpurea will tolerate light or dappled shade and can withstand hot and dry conditions.  Raised beds are highly recommended, especially for moist or clay soils.  Poorly drained soils should be avoided. 

planting

Propagation can be from seed, transplants, or divisions.  When the plant is dormant, divisions can be done from the crowns in early spring or in fall.  Using plants that are older and mature cut the roots into several pieces making sure buds and fibrous roots are included in each division.  Transplant immediately into well-prepared, permanent, planting beds.  (By planting in raised beds, mature echinacea plants can easily be lifted at harvest.)  Space divisions twelve to eighteen inches apart, making rows eighteen to thirty-six inches apart.  Weed control is very important, as echinacea does not compete well with weeds.  Plants will benefit from the use of mulch.      

 Johnny’s Selected Seed Co., Winslow, Maine, recommends the following guidelines for starting seeds indoors.  Echinacea species require light and stratification (pre-chilling) for seed germination.  Using deep containers to allow for good root development, fill with a prepared soil mix, and plant seeds in flats or pots, barely covering the seed with soil.  Moisten, cover, and refrigerate at 40-50⁰F.  Johnny’s has found that E. purpurea does not need the pre-chilling process, but germination can be enhanced if exposed to the cold temperatures for seven days.  After stratification, move flats or pots to warmer temperatures to allow for emergence of the seedlings.  Germination generally occurs ten to twenty days after the stratification process.  When plants are several inches tall (usually eight to twelve weeks after germination), transplant seedlings outdoors in late spring or early summer.  Apply mulch to control weeds. 

 Seeds can be sown directly in the ground in fall or early spring, but a fine seedbed needs to be prepared.  Plant seeds just under the soil surface spacing them two inches apart.  Keep the bed moist and weed-free.  When seedlings emerge, thin plants to the recommended spacing mentioned above.  Studies, from North Carolina State University, showed that E. purpurea plants that were direct seeded into black plastic mulch produced larger plants than E. purpurea plants that were transplanted into plastic mulch.

insects and diseases

Diseases that affect echinacea include the leaf spots Cercospora rudbeckii and Septoria lepachydis and can cause blackening of the leaves.  A root rot, Phymatotrichum omnivorum, has also been identified.  Another disease called “aster yellows disease” is a virus that is transmitted by a leafhopper feeding on echinacea.  Other insects that feed on echinacea include Japanese beetles and thrips. 

harvesting, cleaning, and drying

Echinacea root is harvested in the fall after the plant has gone dormant, usually the second to fourth growing season, depending on which planting method is used - direct seeding, transplanting, or divisions.  A spading fork or other digging tool can be used as well as a modified potato digger.  Shake the roots free of dirt and carefully remove only roots that are echinacea.  It is not acceptable to include foreign particles.  Put plants in the shade until harvesting is complete.  When ready for processing, it is recommended to wash echinacea roots with a pressure hose.  Richo Cech, author of Growing At-Risk Medicinal Herbs, recommends cutting the crowns to remove dirt and small stones that get lodged at the base of the crowns.  Cech recommends processing the echinacea as soon as possible after washing to minimize oxidation.

 Once the roots are cleaned, spread on non-aluminum screens for the drying process.  The roots need a warm location with adequate airflow.  If a drying unit is not available, a large dehydrator, converted greenhouse, or converted rooms in a barn are areas that can be used for drying.  According to Cech, “Dry for one day at 70⁰F, then turn the temperature up to 110⁰F, drying the roots until they snap.”  Cech recommends “storing the dried root in plastic bags in light-proof sacks or drums, in a cool, dark, and dry location for up to one year.”  Reports of estimated yields of the dried root ranged from 1000 to 2500 pounds per acre after three growing seasons.   

 Currently, there is a limited market for the aerial parts (above ground) of E. purpurea.  With sufficient growth, the leaf can be harvested the first growing season and subsequent years to follow.  The final growing season, the root can then be harvested in the fall. 

markets  

Echinacea has a worldwide customer base consisting of large, medium, and small processors.  Demand for the product includes mainstream pharmaceutical companies that use E. purpurea in multi-constituent vitamin and mineral products.  According to ATTRA, National Sustainable Agriculture Information Service, European companies produce more than 280 different products made from E. purpurea, including ointments, lotions, creams, tinctures, liquid and dry extracts, and toothpastes. 

 E. purpurea is being grown on a large scale in the United States (Washington, Oregon, Colorado, Idaho, Iowa, Missouri, New Mexico and Wisconsin), Canada, Germany, Australia, New Zealand and Switzerland.  After a temporary slowdown in the market the past couple years, E. purpurea is enjoying a comeback with demand increasing, especially for a certified organic product.  The challenge to medicinal herb growers is finding a reliable source of seed true to the particular species, since echinacea can cross-pollinate easily.  Growers should buy from a reliable seed source that specializes in selling seed for the medicinal herb industry.

 As a popular perennial in the ornamental trade, there are now many cultivars of echinacea, including varieties that flower white, yellow, and even orange, as well as shades ranging from pale pink to hot pink to deep purple.

Adam, Katherine L. 2002. Echinacea as an alternative crop. ATTRA - National Sustainable Agriculture Information Service. Click here for Web site. pp. 14

Cech, Richo. 2002. Growing At-Risk Medicinal Plants. Horizon Herbs. Williams, Oregon. 314 pp.

 Fernald, M. L. 1970. Gray’s Manual of Botany. D. Van Nostrand Company, New York, NY. 1632 pp.

 Davis, Jeanine. 2002. Pictures, information, and yield estimates of medicinal herbs researched at N.C. State University. North Carolina State University. Raleigh, NC. Click here for Web site.

Greenfield, Jackie, and Jeanine M. Davis. 2004. Medicinal herb production guides. North Carolina State University, Raleigh, NC.

 Hwang, Sheau-Fang, Chang, Kan-Fa, and Ron Howard. 2001. Yellows diseases of echinacea, monarda, and caraway. Agriculture, Food and Rural Development. Crown copyright. Alberta, Canada. 6 pp. Click here for Web site.

Jensen, Beth. 2004. Johnny’s Selected Seeds. Winslow, Maine. Personal communication.

 Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. 1968. Manual of the Vascular Flora of the Carolinas. University of North Carolina Press, Chapel Hill, NC. 1183 pp.

 Strategic Reports. 2002. Analysis of the economic viability of cultivating selected botanicals in North Carolina. A report commissioned for the North Carolina Consortium on Natural Medicinal Products by North Carolina State University, Raleigh, NC. 244 pp.

 Sturdivant, Lee, and Tim Blakley. 1999. Medicinal Herbs in the Garden, Field, and Marketplace. San Juan Naturals. Friday Harbor, Washington. 323 pp.

 US Department of Agriculture, Crops Research Division Agricultural Research Service. 1960. Index of Plant Diseases in the United States, Agriculture Handbook No. 165. Washington, DC. 531pp.

 Westcott, Cynthia. 1960. Plant Disease Handbook. D.Van Nostrand Company, Inc. Princeton, NJ. 825 pp.

The North Carolina Arboretum is grateful to Jackie Greenfield and Jeanine M. Davis for their contributions to this publication, including excerpts from their publication “Medicinal Herb Production Guides”. The Arboretum also wishes to thank Richard Rice for his artistic renditions of the herbs. The Superb Herbs Web site and the documents provided were made possible by a grant from the NC Department of Agriculture and Consumer Services, found on the Web at www.ncagr.com.