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These plants range from 46–120 centimetres (18–47 inches) in height. The flowers are usually yellow with a toothed tip, but can also be yellow-and-red bicolor or pink.[3] They have showy flower heads with involucral bracts in two distinct series of eight each, the outer being commonly connate at the base. The flat fruits are small and dry and look like insects.
There are nearly 40 species of Coreopsis, all of which are native to North, Central, and South America.[1] The name Coreopsis is derived from the Ancient Greek words κόρις (transl. grc – transl. koris), meaning "bedbug", and ὄψις (transl. grc – transl. opsis), meaning "view", referring to the shape of the achene.[4][5]
Coreopsis is a variable genus closely related to Bidens. In fact, neither Coreopsis nor Bidens, as defined in the 20th century, is strictly monophyletic. Coreopsis is best described as paraphyletic. Previously (1936), Coreopsis was classified into 11 sections and 114 species, but the African species were subsequently reclassified as Bidens, leaving the North and South American species, some 75–80 in all, under Coreopsis. 45 species are in the 11 North American sections, and the remaining 35 are in the South American section Pseudoagarista. The North American species fall into two broad groups, with 5 sections and 12 species in Mexico and North America and the remaining 5 sections and 26 species in Eastern North America.[4]
Plants of the World Online accepts the genera AnacisSchrank,[8]ElectrantheraMesfin, D.J.Crawford & Pruski,[9]EpilepisBenth.,[10]LeptosyneDC.,[11] and Silphidium(Torr. & A.Gray) Mesfin & D.J.Crawford,[12] which other authorities, including the Global Compositae Database, treat as synonyms of Coreopsis. Plants of the World Online treats Selleophytum as a synonym of Coreopsis.[13]
North American Coreopsis can be found in two habitats in the wild, growing along roadsides and open fields throughout the Eastern United States and Canada. In this environment the plant will self-sow.
Coreopsis can grow in a garden as a border plant, or in a container, preferring well-drained soil. Deadheading the flowers ensures it does not become weedy. Using the U.S. Department of Agriculture (USDA) hardiness zones will identify what soil and climate is preferred for different cultivars or species.[16] Notable species found in cultivation are C. grandiflora and C. verticillata, as well as their various cultivars.
Coreopsis, Kansas wildflower
The sunny, summer-blooming, daisy-like flowers are popularly planted in gardens to attract butterflies. Both annual and perennial types are grown in the home garden (USDA hardiness zone 7a/6b).[3] In the Mid-Atlantic region, insects such as bees, hover flies, and wasps are often observed visiting the flowers.[3]
All Coreopsis species were designated the state wildflower of the U.S. state of Florida in 1991.[17] In the language of flowers, Coreopsis means to be always cheerful, while Coreopsis arkansa in particular stands for love at first sight.[18]
^ abcKim, Seung-Chul; Daniel J. Crawford; Mesfin Tadesse; Mary Berbee; Fred R. Ganders; Mona Pirseyedi; Elizabeth J. Esselman (July–September 1999). "ITS sequences and phylogenetic relationships in Bidens and Coreopsis (Asteraceae)". Systematic Botany. 24 (3): 480–493. Bibcode:1999SysBo..24..480K. doi:10.2307/2419701. JSTOR2419701.
^"Species Records of Coreopsis". Germplasm Resources Information Network. United States Department of Agriculture. Archived from the original on January 20, 2009. Retrieved February 9, 2011.
^"Genus: Coreopsis L."Germplasm Resources Information Network. United States Department of Agriculture. January 6, 2011. Archived from the original on June 29, 2011. Retrieved February 9, 2011.
^"Coreopsis spectabilis". www.ipni.org. International Plant Names Index. Retrieved 14 April 2024.
^"tickseed". USDA plants website. USDA NRCS National Plant Data Team. Retrieved 27 January 2017.
^Main, Martin B.; Ginger M. Allen. "Florida State Symbols". Electronic Data Information Source. University of Florida IFAS Extension. Retrieved February 9, 2011.
Coreopsis is a genus of flowering plants in the family Asteraceae, consisting of approximately 39 species of annuals, perennials, subshrubs, and shrubs that are primarily native to temperate and tropical regions of North and South America, with some introductions elsewhere.[1][2] Known commonly as tickseeds or calliopsis, these plants typically grow 10–200 cm tall, featuring erect, branched stems; opposite or alternate leaves that are simple, lobed, or pinnately divided; and radiate flower heads with 5–12 yellow (sometimes red-tinged) ray florets surrounding a central disc of bisexual florets.[1] The name Coreopsis derives from the Greek words for "bedbug" and "appearance," referring to the tick-like shape of the obcompressed, often winged cypselae (seeds) that bear two awn-like pappi.[1]Of the roughly 28 species native to North America, many are valued for their ornamental qualities, including vibrant, long-blooming flowers in shades of yellow, pink, red, and bicolors, making them popular in gardens, borders, and native plantings.[1][3] These plants exhibit strong adaptability to various conditions, tolerating poor soils, drought, heat, humidity, and cold, while thriving in full sun and well-drained sites.[4] Ecologically, Coreopsis species support pollinators such as bees and butterflies, contributing to biodiversity in meadows, prairies, and roadsides, and several, like Coreopsis lanceolata, one of the species under Florida's state wildflower (the genus Coreopsis), are used in conservation and restoration projects.[5][6] Numerous cultivars have been developed for horticulture, including award-winners like 'Early Sunrise' and 'Moonbeam,' enhancing their role in landscaping and cut-flower production.[7][8]
General Characteristics
Description
Coreopsis species are primarily annual, biennial, or perennial herbs, though some are shrubby, with heights typically ranging from 10 to 120(–200+) cm, though occasionally reaching up to 300 cm in taller forms.[9] Stems are erect or ascending, often branched, terete to angular (subtetragonal or striato-sulcate), and glabrous to pubescent or hispid, especially at nodes.[9] Perennial species frequently form basal rosettes and may exhibit rhizomatous growth, allowing for vegetative spread, while annuals tend to have a more upright, non-spreading habit.[9]Leaves are opposite (rarely alternate distally), petiolate to sessile, and vary from simple and entire to pinnatifid, bipinnatisect, or compound, with blades linear to ovate, 0.5–20 cm long and 0.3–22 mm wide.[9] Margins are entire to toothed or lobed, and surfaces are glabrous to hispid; perennial species often develop basal rosettes with broader leaves, whereas annuals feature simpler, narrower foliage.[9] A notable example is Coreopsis verticillata, which bears thread-like, finely dissected leaves up to 5 cm long, enhancing its feathery appearance.[10]The inflorescence consists of solitary or cymose to corymbiform arrays of radiate heads, 1–13 cm in diameter, borne on peduncles 1–30 cm long.[9] Each head features (5–)8(–12+) ray florets, typically yellow (rarely pink or red), with ligules 0.7–4.5 cm long and 1.5–9 mm wide, pistillate or sterile, and entire to paucidentate; disc florets are numerous (8–150+), bisexual, fertile, tubular, yellow to reddish, and 5-lobed.[9][1] The involucre is cylindric to hemispheric, 5–10 mm high, with phyllaries in two (rarely more) series: outer ones herbaceous, linear to ovate, 1–24 mm long, and inner ones membranous, lanceolate to oblong, 2.5–14 mm long, with scarious margins.[9]Fruits are obovoid to oblanceolate achenes, 1.2–6 mm long and 0.7–4 mm wide, obcompressed, often winged with thin, membranous margins (integral, fractured, or dentate) or tuberculate, and glabrous to setose.[9] The pappus comprises two short awns (0.5–4 mm) or is absent, with the overall shape resembling a tick, a trait consistent across life forms but more pronounced in winged perennial species compared to the smoother achenes of some annuals.[9]
Etymology and Names
The genus name Coreopsis originates from the Ancient Greek words koris (κόρις), meaning "bedbug" or "bug," and opsis (ὄψις), meaning "appearance" or "resembling," a reference to the distinctive shape of the plant's seeds, or achenes, which resemble small insects.[11][12] This etymology highlights the morphological feature that early botanists found particularly notable about the seeds' elongated, ridged form.[13]Common names for Coreopsis species reflect both this seed characteristic and the plant's ornamental appeal. The name "tickseed" derives directly from the tick-like appearance of the achenes, evoking the shape of a wood tick, and is widely used across North America for various species.[14] "Calliopsis," another frequent common name, stems from Greek kallos (beautiful) and opsis (face or appearance), emphasizing the bright, daisy-like flowers' aesthetic qualities, particularly in cultivated varieties.[15] Regional variants include "golden coreopsis" for yellow-flowered types like C. lanceolata and "threadleaf tickseed" for fine-leaved species such as C. verticillata.The genus was first formally described by Carl Linnaeus in his Species Plantarum in 1753, where he established Coreopsis as distinct within the Asteraceae family, initially including species like C. lanceolata.[16] Early taxonomic efforts encountered confusion with the related genus Bidens due to similarities in seed structure—both feature awned achenes that aid dispersal—but Coreopsis was differentiated by its pappus of typically two (or zero) awns, rather than 2–4 awns in Bidens, along with overall floral morphology.[17] This distinction helped resolve initial misclassifications, though phylogenetic studies continue to reveal close evolutionary ties between the genera.[18]Cultural name variations for Coreopsis are less extensively documented in indigenous languages, with limited records of traditional Native American terms; however, some tribes, such as the Zuni, recognized the plant for practical uses without specific vernacular names preserved in ethnobotanical literature.[19] In modern horticulture, trade names often emphasize hybrid vigor or color, such as "Plains coreopsis" for C. tinctoria cultivars or "Moonbeam" for compact selections of C. verticillata, reflecting its popularity in ornamental gardening.[20][21]
Taxonomy and Systematics
Classification History
The genus Coreopsis was established by Carl Linnaeus in the second volume of Species Plantarum in 1753, where he described five North American species—C. auriculata, C. delphinifolia, C. lanceolata, C. tripteris, and C. verticillata—based on their distinctive cypselae resembling bedbugs in shape, from the Greek koris (bedbug) and opsis (appearance). Note that C. delphinifolia is now classified in the genus Bidens. Early taxonomic efforts encountered significant confusion with the closely related genus Bidens, stemming from similarities in achene morphology, such as winged or awned fruits that facilitated dispersal and blurred generic boundaries.[22]During the 19th century, American botanists expanded the genus considerably through explorations of the New World flora; Thomas Nuttall, in his Genera of North American Plants (1818), described several new species like C. tinctoria and C. palmata, incorporating diverse annual and perennial forms from prairies and woodlands, while subsequent workers added tropical and subtropical taxa, swelling the recognized species count to around 114 by 1900. John K. Small's Flora of the Southeastern United States (1903) further contributed to this growth by detailing regional variants and emphasizing morphological variation in leaf and inflorescence structure, though it perpetuated inclusions of heterogeneous elements without resolving polyphyletic issues.In the pre-molecular era of the 20th century, classifications relied heavily on vegetative and reproductive morphology, often resulting in polyphyletic groupings that lumped unrelated lineages; Earl Edward Sherff's seminal 1936 revision in the Publications of the Field Museum of Natural History organized Coreopsis into 11 infrageneric sections and accepted 114 species, including disparate tropical groups from Mexico, the Caribbean, and Africa, based on traits like phyllary arrangement and achene ornamentation. These morphological approaches highlighted persistent challenges, such as ambiguous distinctions from Bidens via awn barb directionality, which Sherff deemed unreliable for generic delimitation.[22]Twentieth-century revisions began addressing the genus's paraphyly by excluding segregate genera for unrelated clades, notably tropical elements reassigned to genera like Electra and Leptosyne; Daniel J. Crawford's 2005 phylogenetic study using nuclear and plastid sequences confirmed polyphyly and supported a narrowed circumscription to approximately 75–80 species in Coreopsis sensu stricto, focusing on temperate North American core members while recognizing the need for further taxonomic realignments.[23]
Phylogenetic Relationships
Coreopsis belongs to the family Asteraceae, subfamily Asteroideae, and tribe Coreopsideae, where it forms part of a diverse group including genera such as Bidens, Cosmos, and Thelesperma.[24][23]Molecular phylogenetic analyses, primarily using nuclear ribosomal ITS sequences and plastid markers like matK and rpl16, have demonstrated that Coreopsis sensu lato is paraphyletic, with its species distributed across multiple lineages interspersed with other Coreopsideae genera.[25][23] A seminal study by Kimball and Crawford (2004) analyzed ITS data from representatives of 19 Coreopsideae genera and found Coreopsis species scattered in at least three major clades, one closely allied with temperate Bidens and Thelesperma, another with southern Bidens lineages, and a third near Cosmos and related taxa, underscoring the lability of reproductive characters traditionally used for delimitation.[24] Subsequent work by Crawford and Mort (2005) on eastern North American Coreopsis, incorporating both nuclear and plastid sequences, confirmed this paraphyly by showing Bidens species nested within Coreopsis clades, with Thelesperma positioned as sister to the Bidens-Coreopsis complex (100% bootstrap support).[23]Analyses from 2010 to 2020 further highlighted biogeographic patterns, revealing distinct North American clades separate from South American ones, as evidenced in Crawford et al. (2009) and a 2014 study on section Pseudoagarista using combined cpDNA and ITS data.[26][27] The latter demonstrated non-monophyly of the section, with Mexican and South American subclades forming separate monophyletic groups but not aligning as a single entity within Coreopsis, suggesting multiple polyploid origins and rapid radiations in southern lineages.[27] These studies collectively propose taxonomic revisions that could split Coreopsis sensu lato into 5 to 11 segregate genera to achieve monophyly, though no comprehensive formal revision has been implemented.[26][27]As of 2025, Plants of the World Online recognizes approximately 39 accepted species in a narrowed core Coreopsis, reflecting ongoing caution in taxonomic changes pending further integrative evidence. A 2023 monograph by Tadesse and Crawford proposes further splits, recognizing Coreopsis s.s. (with about 18 species) alongside new genera such as Burnellia, Gyrophyllum, Pseudoagarista, and Silphidium.[2][28]
Infrageneric Sections
The infrageneric classification of Coreopsis currently recognizes 11 sections, as established in Crawford (2006) and with minor updates reflected in Plants of the World Online as of 2025. This system integrates morphological traits, such as achene structure and leaf morphology, with molecular phylogenetic data from nuclear and plastid sequences to delineate monophyletic groups. The sections primarily encompass North and Central American species, with diagnostic features including variations in achene wings (winged or wingless), phyllary shapes (outer phyllaries often lanceolate or ovate), and chromosome numbers, where most taxa exhibit a base of 2n=26. However, a 2023 monograph proposes elevating several sections to generic rank, including Pseudoagarista, Gyrophyllum, Silphidium, and Burnellia, potentially reducing Coreopsis s.s. to three sections with ~18 species.[26][29][28]Section Coreopsis is one of the core groups, containing 7 species of perennial herbs native to North America, distinguished by the presence of pappus scales on the achenes and simple to pinnatifid leaves. These species typically occur in eastern and southern United States habitats like prairies and open woodlands.[29]Section Silphidium comprises rhizomatous perennials, exemplified by C. palmata, with broad, palmately lobed leaves and robust stems; achenes are often wingless and lack awns, adapted to mesic forest edges in the central U.S. (proposed as genus Silphidium in 2023).Section Electra includes annual species with palmately compound leaves and winged achenes, primarily distributed in the southwestern U.S. and Mexico, where they thrive in disturbed, arid sites.[26]Section Leptosyne features Mexican species with narrow, linear leaves and finely dissected foliage, often with awned achenes; these are adapted to rocky, montane environments in northern Mexico (now often treated as separate genus Leptosyne).[30]Other sections include Anathysana, characterized by monotypic or small groups with unique ray floret coloration and outer phyllaries fused at the base; Calliopsis, annuals with deeply lobed rays and red-centered disks, common in plains; Eublepharis, perennials with eyelashed phyllaries and wingless achenes, eastern U.S. endemics; Gyrophyllum, with spiral-twisted leaves and tuberculate achenes in southeastern wetlands (proposed as genus Gyrophyllum in 2023); Pseudoagarista, high-elevation Mexican perennials with pubescent stems and narrow achenes (proposed as genus Pseudoagarista in 2023); Pugiopappus, featuring pugioniform (dagger-shaped) pappus scales and succulent leaves in coastal areas; and Tuckermannia, Californian taxa with thread-like leaves and dimorphic achenes. Some sections, such as Anathysana and Silphidium, are monotypic, while others like Pseudoagarista show signs of paraphyly. The 2023 monograph represents a major update to this framework, though not yet fully adopted in all databases as of 2025.[29][28]
Accepted Species
According to Plants of the World Online (accessed November 2025), the genus Coreopsis includes 39 accepted species, all native primarily to North and South America.[2]Among the accepted species, Coreopsis lanceolata serves as the generitype and is a widespread perennial found across eastern North America, characterized by lance-shaped leaves and yellow ray florets.[31]Coreopsis verticillata, known as threadleaf coreopsis, is a perennial ornamental species valued for its finely dissected foliage and prolonged blooming period.[32] The annual Coreopsis tinctoria, or plains coreopsis, features bicolored flowers and is commonly included in native wildflower restorations.[33] Regional endemics such as Coreopsis petrophila, the rock tickseed, are restricted to rocky outcrops in western Mexico.Taxonomic variability within Coreopsis has led to several synonyms; for example, Coreopsis drummondii is now regarded as a synonym of Coreopsis basalis.[34] No new species have been accepted since 2020, with recent efforts emphasizing phylogenetic clarification rather than novel descriptions.[28]Phylogenetic revisions since 2006 have excluded numerous taxa formerly placed in Coreopsis, transferring approximately 35 species to other genera; notable examples include Coreopsis bigelovii, now classified as Leptosyne bigelovii.[35] These reclassifications, informed by molecular data, have narrowed Coreopsissensu stricto to core clades while elevating former sections like Pseudoagarista to generic rank.[36]
Biogeography
Native Distribution
Coreopsis is native to the Americas, with the genus encompassing approximately 40 species primarily distributed across North, Central, and northern South America.[1][2] The majority—around 80%—occur in the United States, with 28 species documented in North America north of Mexico, including parts of Canada and extending southward into Mexico.[1] Central American populations are present in countries such as those in the tropical New World region, while northern South American extensions include Colombia and Peru, with disjunct occurrences in the Caribbean, such as on Hispaniola.[2][37]Centers of diversity for Coreopsis are concentrated in the southeastern United States, the Mexican highlands, and the Andes.[23]Florida alone hosts over 10 native species, including endemics like Coreopsis floridana, reflecting high regional endemism in open, sandy habitats.[38] In Mexico, species such as Coreopsis mutica thrive in highland areas, contributing to the genus's diversity in subtropical and temperate zones.[39] Caribbean disjunctions, as seen in species on Hispaniola, highlight isolated populations likely resulting from historical biogeographic events.[2]Distribution patterns within the genus vary by life form and habitat. Annual species, such as Coreopsis tinctoria, are widespread across North American prairies and open plains, often in disturbed or meadow settings.[20] Perennial species predominate in eastern woodlands and coastal plains, exemplified by Coreopsis verticillata in the southeastern U.S.[40] Southern extensions of some distributions are attributed to post-glacial migrations following the Last Glacial Maximum, allowing northward recolonization from refugia in the southeastern U.S. and Mexico.[23]While Coreopsis is exclusively native to the New World, rare naturalized introductions occur outside the Americas, such as in parts of Europe and Asia, but no species are indigenous to the Old World.[2] These extralimital populations are typically limited to disturbed sites and do not form established wild ranges.[1]
Habitat Preferences
Coreopsis species exhibit a broad range of habitat preferences, primarily favoring well-drained soils including sandy, loamy, or rocky substrates, which support their drought tolerance once established. These plants thrive in full sun to partial shade, with many species adapted to poor or nutrient-low soils that prevent excessive vegetative growth at the expense of flowering. For instance, Coreopsis lanceolata prefers sandy or clay loam soils and demonstrates moderate drought tolerance in open, sunny conditions.[41] Similarly, Coreopsis verticillata occurs in dry, sandy or rocky soils within wood edges and pine savannas, tolerating low moisture levels.[42]While most Coreopsis are adapted to drier conditions, certain species occupy wetter microhabitats; Coreopsis rosea, for example, grows in damp, sandy to peaty shores, depressions, and meadows, requiring high soil moisture and full sun to partial shade.[43] Across the genus, moisture preferences vary from low (e.g., in rocky ridges for Coreopsis palmata) to medium or high, but all species generally avoid waterlogged soils to prevent root rot.[44] Microhabitats commonly include open fields, roadsides, disturbed prairies, and savannas, where Coreopsis gigantea clings to rocky sea cliffs and exposed dunes up to 150 feet elevation, while Coreopsis calliopsidea inhabits dry, open gravelly sites from 500 to 3,200 feet.[45][46] In the southeastern United States, species like Coreopsis auriculata favor thin woods, thickets, and woodland openings, often in fire-maintained pine savannas that promote species diversity through periodic burning.[47][48]The genus spans temperate to subtropical climates.[49] Annual species, such as Coreopsis tinctoria, thrive in arid prairies and plains, self-seeding reliably in disturbed, moist sandy soils during wet years.[20] Elevations range from sea level along coastal dunes to over 3,000 meters in Mexican highlands, where species like Coreopsis petrophila adapt to rocky outcrops and variable elevations in regions such as Jalisco and Durango.[50] This elevational versatility underscores the genus's adaptability to diverse topographic features, from low-elevation meadows to montane disturbed areas.
Ecology
Pollination and Interactions
Coreopsis species are primarily entomophilous, relying on insect pollinators for reproduction, with flowers producing nectar and abundant pollen to attract visitors. Small bees, particularly halictids (e.g., Halictus spp.) and other native species such as Ceratina (small carpenter bees), Megachile (leafcutter bees), and Melissodes (long-horned bees), dominate visitation, accounting for over 77% of observations in some studies, while bumblebees (Bombus spp.), honeybees (Apis mellifera), and carpenter bees (Xylocopa spp.) also contribute significantly. Butterflies, including sulphur butterflies (Colias spp.), and syrphid flies (hoverflies) visit less frequently but aid in pollen transfer, with Diptera overall attracted to the bright ray florets and composite structure of the inflorescences.[51][52][53][54]Most Coreopsis exhibit self-incompatibility, a genetic mechanism that prevents self-fertilization and promotes outcrossing to enhance genetic diversity, as documented in species like C. lanceolata and C. rosea through bagging and pollination experiments showing near-zero seed set from self-pollen. This breeding system results in seed sets of approximately 30% of ovules following cross-pollination, supporting robust reproduction in natural populations. Pollen-ovule ratios further indicate xenogamy (outcrossing) as the predominant mode, though some variation exists across species. The ray florets, often yellow or red, serve as visual attractants to guide pollinators to the disc florets where reproduction occurs.[53][55][56][57]Seed dispersal in Coreopsis occurs mainly through zoochory, facilitated by the tick-like shape of the achenes, which have barbed or sticky surfaces that readily attach to fur, feathers, or clothing of passing animals and humans, enabling epizoochory over short to moderate distances. Some species, such as C. lanceolata, also exhibit anemochory due to thin, winged pappi or extensions on the achenes that aid wind transport, contributing to polychorous dispersal strategies including autochoric release near the parent plant. This dual mechanism enhances colonization of disturbed habitats.[58][59][60]Coreopsis serves as a larval host for certain Lepidoptera, notably the silvery checkerspot butterfly (Chlosyne nycteis), whose caterpillars feed on the foliage, integrating the plant into butterfly life cycles. Fungal interactions are minor, with arbuscular mycorrhizal fungi (AMF) such as Glomus mosseae forming symbiotic associations that enhance nutrient uptake in some species, though no major dependencies are documented, as plants can survive without them. Chromosome numbers, commonly 2n=26 (base x=13) in diploids like C. grandiflora and C. lanceolata, influence hybridization potential, with polyploids (e.g., 2n=52) occasionally forming viable interspecific crosses that affect breeding outcomes.[61][62][63][64][65][66][67][68]
Ecological Role and Threats
Coreopsis species contribute significantly to ecosystem stability in their native North American habitats, particularly in prairies and open disturbed areas where they act as soil stabilizers through their fibrous root systems, helping to prevent erosion on slopes and revegetated sites.[69][70] As perennial forbs, they provide nectar resources that support a range of pollinators, including bees and butterflies, while their seeds serve as food for birds and small mammals, and foliage is browsed by herbivores such as rabbits and deer.[69] In disturbed habitats like roadsides and glades, Coreopsis often functions as a pioneer species, indicating early successional stages and facilitating biodiversity recovery by colonizing gaps and supporting associated wildlife.[71][72]These plants face multiple threats that undermine their ecological contributions, primarily habitat loss from urbanization, agriculture, and development, which fragments prairies and coastal plains essential for their persistence.[73][74]Invasive species competition, often intensified by eutrophication from nutrient runoff and hydrological alterations like lake drawdowns, displaces native Coreopsis populations in wetland and shoreline habitats.[57]Climate change exacerbates these pressures by shifting suitable habitats and disrupting perennial growth cycles, potentially reducing their role in pollinator support and soil retention.[74]Conservation status varies across species, with several recognized as endangered or threatened due to these threats; for instance, Coreopsis rosea (pink coreopsis) holds a global rank of G3 (vulnerable, reviewed September 2024) and is listed as endangered under Canada's Species at Risk Act.[74] Other species, such as C. stillmanii and C. integrifolia (fringeleaf tickseed), are state-endangered in the U.S., with C. bakeri similarly protected (G1 as of November 2024); several species receive state-level or NatureServe designations highlighting risks to southeastern endemics from ongoing habitat degradation.[75][76][77][78] Restoration efforts in Florida incorporate Coreopsis into roadside wildflower programs, enhancing pollinator corridors and native biodiversity while reducing maintenance needs along highways.[79]Despite these initiatives, gaps persist in understanding Coreopsis resilience, with limited studies since 2020 examining climate impacts on their perennial traits and ecosystem services.[80] Their established value as nectar sources positions them ideally for broader integration into pollinator gardens, though such applications remain underexplored in conservation planning.[81]
Human Interactions
Cultivation
Coreopsis species are propagated primarily through seeds for annual varieties and division or rhizome cuttings for perennials. Annuals like Coreopsis tinctoria are sown directly outdoors in spring after the last frost, with seeds germinating in 7 to 21 days at soil temperatures of 18 to 24°C; indoors, start seeds 6 to 8 weeks prior in a moist, light-exposed medium at around 21°C. Perennials such as Coreopsis verticillata are best divided in early spring or fall every 2 to 3 years to maintain vigor, separating clumps with healthy roots and replanting at the same depth.[14][82][83]These plants thrive in full sun with at least 6 to 8 hours of direct light daily and well-drained, loamy or sandy soils with a pH of 6.0 to 7.0, mimicking the natural drainage of their native habitats to prevent root rot. Space plants 30 to 45 cm apart to allow for air circulation and mature spread of 30 to 60 cm; they tolerate poor, rocky, or sandy conditions but perform best with moderate watering during establishment, becoming drought-tolerant thereafter. Amend heavy clay soils with compost or sand to improve drainage, and avoid over-fertilizing, as excessive nutrients can reduce blooming.[14][83][82]Most Coreopsis are hardy in USDA zones 4 to 9, with some species extending to zone 3; mulch roots in colder areas for winter protection. Maintenance is low: deadhead faded flowers regularly to encourage continuous blooming through summer and into fall, and shear back by one-third in mid-summer for tidier foliage and potential rebloom. They exhibit high resistance to pests and diseases but may occasionally attract aphids or slugs, which can be managed with insecticidal soap or barriers; fungal issues like powdery mildew are rare in well-drained sites with good airflow.[14][83][82]Popular cultivars include 'Moonbeam', a compact hybrid of C. verticillata with pale yellow flowers on 45 to 60 cm stems, prized for its fine-textured foliage and long bloom period in zones 3 to 9. 'Zagreb', another C. verticillata selection, features bright golden-yellow blooms on 30 to 45 cm plants and arises from inter-sectional breeding efforts for enhanced garden performance. These and similar hybrids, such as 'Early Sunrise' from C. grandiflora, offer extended color and vigor through selective crosses.[83][14][82]
Ornamental and Cultural Uses
Coreopsis species are prized in ornamental gardening for their bright, daisy-like flowers and extended blooming seasons, typically from summer through fall, providing reliable color in various settings.[84][85] These plants thrive in borders, wildflower meadows, and containers, where their upright or mounding habits and low-maintenance nature make them ideal for enhancing garden landscapes with minimal effort.[86][87] Selective breeding has diversified their appeal, yielding cultivars in traditional yellows alongside bicolored, pink, red, and orange varieties that suit contemporary aesthetic preferences.[88][89]Culturally, the genus Coreopsis holds notable significance in the United States, particularly as the official state wildflower of Florida and Mississippi, both designated in 1991 to honor its native diversity and vibrant display across the regions.[90][91]Indigenous peoples, including various Native American tribes, have long incorporated Coreopsis into traditional practices, using flower extracts to produce yellow dyes for textiles and preparing root or plant teas as remedies for diarrhea, internal pains, and to strengthen the blood.[20][92][93]In modern applications, Coreopsis contributes to sustainable landscaping by supporting pollinators such as bees and butterflies through its nectar offerings, making it a favored choice for ecologically minded gardens.[61][87] The flowers also feature in floral arrangements, where they symbolize cheerfulness, joy, and optimism, often selected to convey positivity and simple pleasures.[12][94] Commercial dye production from Coreopsis remains limited, mostly pursued in artisanal contexts rather than large-scale manufacturing.[95]Historically, Coreopsis was introduced to European gardens in the 18th century, rapidly adopted for its ornamental qualities and ease of cultivation among early botanists and horticulturists.[96][97] It lacks prominent mythological associations in major cultural traditions, distinguishing it from more symbolically laden plants.[92]
Data related to Coreopsis at Wikispecies
Media related to Coreopsis at Wikimedia Commons
