Echinacea – Americana in the Garden
Echinacea or coneflower is a member of the daisy or sunflower family (Asteraceae) and native almost exclusively to the eastern and central United States. Both narrow-leaf coneflower, Echinacea angustifolia and purple coneflower, Echinacea purpurea were used as traditional medicines by Native Americans. The tribes used physical applications to treat wounds, burns, and insect bites; chewed the roots to treat toothache and throat infections; and ingested the plants to treat pain, coughs, stomach cramps, and snake bites. Early pioneers traveling west across the plains were quick to pick up on the healing properties of this species. The first Echinacea preparation, known as Meyers Blood Purifier, arrived on the market around 1880, as an elixir for rheumatism, neuralgia, and rattlesnake bites.
John Banister, an English clergyman and naturalist, is credited with introducing E. purpurea to Britain, sending the first seeds in the mid-1680s to the Bishop of London, so that they could be planted in the Oxford Botanic Garden. By the late 1800s, purple cone flower was popular in European gardens as both a medicinal herb and as an ornamental flower. Echinacea remains one of the most popular herbal supplements in the U.S.A.
With the growing emphasis on incorporating native plants in home gardens to produce beneficial ecosystems, Echinacea has again surged in popularity. Part of this popularity is due to the development of native cultivars. These cultivars have introduced Echinacea in dazzling colors, in compact forms, with longer bloom periods, and stiffer stems. This tough, beautiful inhabitant of the Great Plains has become the subject of a cultivar explosion.
Like all plants in the family Asteraceae, Echinacea flowers are inflorescences, a collection of 200-300 small fertile disk florets bunched together on the cone. The genus name, Echinacea, comes from the Greek word echinos, meaning hedgehog, referring to the sharp spines that protrude from the disk florets. The disk florets are surrounded by a ring of sterile ray florets or what we refer to as petals. The brightly colored ray florets attract pollinators to the disk florets where pollination occurs.
Echinacea species generally have a basal rosette of foliage and annual stems that arise each season from an underground rhizome or taproot. Purple coneflower (E. purpurea) has a fibrous root system, which makes it easier to transplant in the garden. Its leaves are broad, smooth, and usually toothed. All other Echinacea species have taproots, and leaves that are narrow, hairy, and usually entire (margins without teeth or serration).
Identification of the number of species within the genus has varied throughout its history. Although there is still some inconsistency among sources, most agree on a list of nine species and four subspecies (McGregor, 1968). The species are found naturally growing in habitats from prairies to open woodlands and savannas, often on dry, rocky, or sandy soils in USDA Hardiness Zones 3-9.
Average height for the nine species ranges from about 1′-3’ with E. purpurea growing to 4’ tall and E. laevigata to 5’. Three of the species are used for medicinal purposes: E. angustifolia, E. pallida, and E. purpurea. The species E. purpurea, the purple coneflower, is the most readily available and the one most commonly grown in home gardens.
E. angustifolia: Narrow-leaf coneflower or Black Samson
E. atrorubens: Topeka purple coneflower
E. laevigata: Smooth purple coneflower Federally listed endangered species found in the Piedmont regions. This plant had much of its habitat destroyed when areas were converted to pine plantations.
E. pallida: Pale purple coneflower The states of Tennessee and Wisconsin list the species as threatened, mostly due to habitat loss and over-collection of roots, which are harvested for herbal medicine.
E. paradoxa: Yellow coneflower. Central disk is dark brown and conical. Ray flowers vary from yellow (E. paradoxa var. paradoxa found in the Ozarks) to light purple (E. paradoxa var. neglecta, found only in Arbunkle Mtn. area of Oklahoma).
E. purpurea: Purple coneflower. Ray flowers vary from rose to deep purple, rarely white.
E. sanguinea: Sanguine purple coneflower. It is the southernmost Echinacea species. The specific epithet sanguinea, which is Latin for “blood”, refers to the color of the petals.
E. simulata: Wavy leaf coneflower. Pollen is yellow which helps distinguish it from E. pallida.
E. tennesseensis: Tennessee purple coneflower The official wildflower of Tennessee. In 1979, it was one of the first plants to be listed as endangered by the U.S. but was removed from the list in 2011 after successful conservation efforts to restore populations. Seeds are available commercially. Note in the photo above the upturned ray florets or petals, a characteristic that differentiates this species.
Echinacea reproduces only by seed in the wild. Coneflowers cannot self-pollinate and must rely on insects to transfer pollen between plants to insure successful seed development. Insect pollinators include a diverse mix of flying insects including native bees, wasps, and butterflies. Where Echinacea species overlap in the wild, pollinators carry pollen from one species to another; there are many populations of naturally-occurring interspecies crosses with intermediate traits. Flowering typically occurs from early to late summer. Only a small percentage of seeds that mature in the fall germinate. Seedlings in the wild grow slowly, sometimes taking up to three years for a small rosette of basal leaves to put out a flower stalk.
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. As coneflower habitats decrease in the wild, seed banking efforts have helped prevent this popular flower from becoming extinct.
Echinacea will reseed itself in the garden. In fact, many coneflowers in the garden are new plants from reseeding that have replaced the originals. Mature clumps of coneflowers (3-4 years) can be divided in spring or fall. Although they are most commonly grown from seeds or divisions, coneflowers also grow from taproot cuttings taken in late autumn or early winter when the plant is dormant.
Coneflowers prefer well-drained, moist loam, but can tolerate a variety of soils including poor soils. They are tolerant of both acidic and alkaline soils in a pH range of 6-8. Coneflowers are not heavy feeders. In the absence of a soil test, they can be maintained with an application of a slow release fertilizer at a rate of 1 pound per 100 square feet in late March or early April, just before new leaves emerge. Echinacea likes well-drained soils, and for a number of the new cultivars, excellent winter soil drainage is essential or they may become short-lived perennials. Deadheading, though not necessary, results in some reblooming later in the season and prevents reseeding when not desired. Alternatively, seed heads left on the plants provide food that attracts seed-eating birds including juncos and finches, especially goldfinches.
DISEASES AND PESTS
Echinacea is subject to several diseases such as stem rots, powdery mildew, anthracnose, and aster yellows, as well as damage from aphids, Japanese beetles, and eriophyid mites. Proper spacing will increase air circulation between plants to keep leaves dry and help prevent the spread of powdery mildew and diseases. Removing plant debris also helps to reduce disease problems.
Aphids can be treated by spraying with a hose. Insecticidal soap sprays can be used for more serious infections. Eriophyid mites are microscopic in size and live inside the flower buds where they suck nutrients from the flowers. Damage results in tufts of stunted and distorted flower parts sprouting from the coneflower. Plants that are affected by eriophyid mites should be cut back to the ground in the fall and all plant debris should be removed and destroyed.
Aster Yellows is transmitted to the plant as leafhoppers feed on the plant. This disease causes a witches broom in the flower head, occasional greening of the petals, and stunting. Infected plants should be promptly removed and destroyed to prevent further spread of the disease.
There are now over 200 Echinacea cultivars. Echinacea hybrids are sometimes marketed as Echinacea hybrida, Echinacea x hybrida, or simply with the genus and cultivar name, e.g. Echinacea ‘Sunrise.’
The popularity of Echinacea started to surge after a few landmark cultivar developments. In 1997, Jan van Winsen of The Netherlands found a double-flowered seedling in his cut flower fields. It was the first of its kind in the world. It was eventually successfully marketed as ‘Razzmatazz’ in 2003. The cultivar was an immediate hit and led to the breeding and release of many other double-flowered purple coneflowers.
German horticulturalists had been working since the 1960s on selecting cultivars of E. purpurea, and E. purpurea ‘Magnus’ was the break-through cultivar. It was introduced to commerce by German seedsman Klaus Jelitto, originally being selected from native U.S. plants by Swedish nurseryman Magnus Nilsson near Paarp, Sweden. The 1998 Perennial Plant of the Year award from the Perennial Plant Association catapulted ‘Magnus’ into the spotlight. Consumers loved its bold, giant flowers with rosy purple petals that spread out flat rather than drooping like most coneflowers.
Another huge boost of attention came from the cultivar introductions by Jim Ault, Ph.D., Director of Ornamental Plant Research at the Chicago Botanic Garden. Cross-pollinating by hand, it took him 6 years and more than 200 plants to get his first introduction, Echinacea ‘Art’s Pride’, a cross between E. purpurea ‘Alba’ and E. paradoxa (yellow coneflower). Ault had succeeded in developing the first orange coneflower, which caused a sensation in 2004. Ault went on to introduce many cultivars in the Meadowbrite™ series, including ‘Pixie’, ‘Orange’, ‘Mango’ and ‘Burgundy Fireworks’, and many other cultivars as well. In addition, ItSaul Plants in Atlanta was also developing Echinacea cultivars and introduced the Big Sky™ series.
Note: Many cultivars are sterile, which means they don’t produce seed that can be used by wildlife, nor can they self-seed in the garden to maintain the presence of a desired plant. Sterile cultivars can still produce pollen but the ability to produce pollen and nectar seems to be specific to a particular cultivar. Double-flowered varieties are sterile or near sterile, and have reduced quantity and/or accessibility of floral rewards. The question of whether native cultivars may be substitutes for native species in terms of maximizing attractiveness to pollinators is a complex and relatively new research topic that will be discussed in the July issue of The Garden Shed. Annie White of the University of Vermont is working on trial studies of pollinator attractiveness which include Echinacea cultivars. Douglas W. Tallamy, author of Bringing Nature Home and Nature’s Best Hope is also continuing work on pollinator trials with Mount Cuba and the University of Delaware.
Herbal supplement sales are expected to reach $8.5 billion globally by 2025, with Echinacea representing the largest percentage. In 2017, the Echinacea segment accounted for the largest revenue share, 34.9% of the global market. According to the HerbalGram data published in 2017, Echinacea is the most prominent and third most popular herbal supplement in the mainstream retail distribution network in the U.S.A.
In Germany, herbal supplements are regulated by the government and are offered by prescription. Much of the research on the efficacy of Echinacea has been done in Germany. The products on the market are manufactured in a variety of ways, include numerous species harvested from many sources and use different plant parts. In addition, there are problems concerning the botanical identity of Echinacea species used in commercial preparations. The lack of standardization may contribute to the lack of rigorous clinical evidence supporting the diverse claims implied for these products.
Many studies have been done on Echinacea and the common cold, but there is no confirming evidence for curing a cold or for reducing the chances of catching a cold. Much less research has been done on the use of Echinacea for other health purposes, such as boosting the immune system. Currently, the National Center for Complementary and Integrative Health (NCCIH) is funding research to identify the active constituents in Echinacea and to study the effects on the human immune system of substances in bacteria that live within Echinacea plants.
Native Echinacea species are dwindling in the wild from loss of habitat, slow recolonization, and over-harvesting for the herbal industry. Despite the presence of many large herbal farms that grow Echinacea, professional wild harvesters take up to 200,000 lbs. of Echinacea root every year, faster than the species can regenerate.
With its ability to “make do” in less-than-ideal conditions, E. purpurea is a welcome addition to sunny perennial gardens. It is drought tolerant, deer resistant, and accepting of many types of soil conditions, including poor soils. It self-seeds in the garden, has a long bloom time, and attracts pollinators. High pH? Fine. Low pH? That’s okay, too. Purple coneflower needs good drainage, but is that too much to ask? There is a plethora of Echinacea cultivars on the market, offering a range of heights from the front to the back of the garden. The colors are dazzling. The trade-off might be that not all cultivars are beneficial to pollinators, or a particular cultivar may not be as hardy or as long-lived as the straight species. If you want to live on the wild side, you could try a few cultivars just for fun. But don’t abandon E. purpurea. It’s earned its place.
“From Nursery to Nature: Evaluating Herbaceous Flowering Plants Versus Native Cultivars for Pollinator Habitat Restoration,” University of Vermont, ScholarWorks @ UVM, Graduate College Dissertations and Theses, Annie White, 2016, https://scholarworks.uvm.edu/graddis/626/
Echinacea purpurea ‘Magnus’, University of Vermont Extension, http://pss.uvm.edu/ppp/jan98per.html
“Coneflowers for the Mid-Atlantic Region,” Mt. Cuba Center Research Report 2009, Jeanne Frett and Victor Piatt, https://mtcubacenter.org/trials/echinacea/
“The Conservation Status of Echinacea Species,” Kansas Biological Survey, University of Kansas, Edited by Kelly Kindscher, www.fs.usda.gov › FSE_DOCUMENTS › fsm91_054353
“From Prairie to Garden,” Chicago Botanic Garden, Beth Botts, https://www.chicagobotanic.org/plantinfo/prairie_garden
“Coneflowers: Native Vs. Hybrid,” Dyck Arboretum of the Plains, Katie Schmidt, https://dyckarboretum.org/coneflowers-native-hybrid/
“Native Cultivars versus Native Plants & Their Attractiveness to Pollinators,” Kim Eierman, Ecobeneficial, https://www.ecobeneficial.com/2014/04/native-cultivars-vs-native-plants/
Echinacea, Clemson Cooperative Extension, Home and Garden Information Center, https://hgic.clemson.edu/factsheet/echinacea/
“A Better Cone Flower?” The Chicago Tribune, Beth Botts, 8/26/2007, https://www.chicagotribune.com/news/ct-xpm-2007-08-26-0708230311-story.html
“Insecticidal Soaps for Garden Pest Control,” Clemson Cooperative Extension, https://hgic.clemson.edu/factsheet/insecticidal-soaps-for-garden-pest-control/
“Echinacea Explosion – The Coneflower Chronicles,” Plant Delights Nursery, https://www.plantdelights.com/blogs/articles/purple-coneflower-echinacea-purpurea-plant
“Echinacea purpurea Root,” American Botanical Council, http://cms.herbalgram.org/expandedE/EchinaceaPurpurearoot.html?ts=1589908161&signature=4b9b1f4ed678301c51bac4d322d0b32e
“Echinacea for Preventing and Treating the Common Cold,” NCBI, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367446/
Feature Photo: E. purpurea, purple coneflower, Photo: H. Zell, Wikimedia Commons