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Name: Campsis radicans (L.) Bureau

Common Names:  Trumpet vine (4), Trumpet-creeper(1), Cow-itch vine (4), Trumpet-flower (1)

Family: Bignoniaceae, the Bignonia or Trumpet-creeper Family

Etymology: Campsis comes from the Greek kampsis, or “curve”, referring to the curved stamens of the genus (5).  Radicans is latin for “rooting”, a reference to the species’ aerial roots (9).

Botanical synonyms: Bignonia radicans L. (4), Tecoma radicans Juss (5).

Quick Notable Features:
¬ Tube-shaped orange and red flowers
¬ Large, opposite, pinnately compound leaves
¬ 7-15 coarsely serrate leaflets per leaf

Plant Height: Has been found growing 20 meters into tree crowns (9) and to the tops of telephone poles (7). 

Subspecies/varieties recognized: Campsis radicans var. speciosa, as well as various horticultural cultivars.

Most Likely Confused with: Bignonia capreolata, Campsis grandifolia, Tribulus terrestris, Lonicera sempervirens, Wisteria frutescens, Wisteria sinensis 

Habitat Preference: Along the edges of woods, on fences and hedges, railways and roads, growing up utility poles and trees (7).

Geographic Distribution in Michigan: Although not native to Michigan, C. radicans can be found across the southern half of the state as an escapee from gardens, largely along developed routes (1).

Known Elevational Distribution: Found in the Smoky Mountains at altitudes of 2000 feet but may have been introduced there (6).

Complete Geographic Distribution: Native to the eastern United States from Iowa and New Jersey south to Texas and Florida (7), and west through Kansas (9). Naturalized northwardthrough Ohio (8), into New England (7), Michigan (1), and North Dakota, as well as California, Washington, Utah, and Colorado (16).

Vegetative Plant Description: This climbing, sprawling, or trailing woody vine is perennial. The stems have pale bark and yellowish wood with long internodes.  The older stems may be stiff with peeling bark, while the younger stems are smooth and flexible.  The opposite leaves are pinnately compound with 5-13 leaflets borne on short petiolules (7).  The leaflet blades are rounded to oblique at the base, lanceolate to ovate, and paler below than above, usually with pubescence along the midrib (7). Campsis has five sets of nectaries; one large floral set and four smaller sets on the calyx, corolla, fruit, and extraflorally on the petioles (13).

Climbing Mechanism:  Adventitious aerial roots are borne along older portions of the stem (9).  These lodge in cracks in bark or on trellises, aiding in support while the main stem generally grows straight upward (pers. obs. R. J. Burnham).

Flower Description: The inflorescence is a terminal, compound cyme, often with 10-20 bisexual flowers, which may not bloom all at once (7,12). The calyx is campanulate to cylindrical, orange and leathery with five lobes (12). The corolla is cylindrical and flaring, red-orange, with a yellow and red striped interior that is a quarter the length of the calyx (7,12).  Two pairs of didynamous stamens (two lengths) with pollen sacs and one staminode (without pollen sacs) are located at the top of tube, but do not extend beyond the calyx (11).  The single, two-carpellate pistil has a slim, superior ovary with one two-lobed stigma and is surrounded by a large nectar disc (11,12).

Flowering Time: June to September across its native range (12); while the flowering season in Michigan may be shorter.

Pollinator: The red, tube-shaped flowers are known to attract hummingbirds (1).

Fruit Type and Description: The fruit is a two-part dehiscent capsule, 10-20cm long, with two locules and a slight groove along its suture. It is elongated and irregularly cylindrical, as well as tapered at either end (7, 12).

Seed Description: The seeds are flattened and brown with translucent wings on either side, 1.5-2cm (12). 

Dispersal Syndrome: Seeds of Campsis are winged, so they are most likely dispersed via wind.

Distinguished by: Bignonia capreolata is commonly known as cross-vine or trumpet-flower and in some areas it may be considered to be the same species as Campsis radicans.  However, the corollas of Bignonia capreolata have yellow linings, and the leaves have only one or two leaflets with generally entire margins and a terminal tendril (8). Campsis grandiflora does not grow as high, has few adventitious roots, and has larger, showier flowers (10). In addition, Campsis grandiflora has glabrous leaves and rounded capsule tips (14).  Tribulus terrestris is far more hairy than Campsis radicans, has entire leaflet margins, and is more a creeper than a climber.  While Lonicera sempervirens has similarly colored and shaped flowers, its simple leaves should immediately distinguish it from Campsis.  Wisteria frutescens and Wisteria sinensis have alternate leaf arrangement and entire leaf margins, although the leaflets of Wisteria sinensis may seem undulate.

Other members of the family in Michigan: There are two species of Catalpa in Michigan (5).

Ethnobotanical Uses: The roots of Campsis are known to induce sweating and may help heal wounds; NOTE: the leaves may cause a skin rash (15).

Phylogenetic Information: The Bignoniaceae are derived within the order Lamiales which is a part of the euasterids I, of the eudicots (17).  Some sources list Bignoniaceae within the Scrophulariales, while others have merged the Scrophulariales with the Lamiales (11, 17).  Either way, Bignoniaceae is closely related to Oleaceae (11) and Campsis is a member of the Bignoniaceae tribe Tecomeae (L. Lohmann pers. comm. 11/07).

Interesting Quotation or Other Interesting Factoid not inserted above:
-There are accounts in the southern United States of Campsis becoming highly invasive and sending up shoots several meters away from the main trunk (10).
–Campsis is attractive to several ant species due to its complex, extrafloral nectarines.  The ants protect Campsis from herbivory (13).
-Bignoniaceae is largely a tropical family, although several members may be found as cultivars across the southern U.S.  There are only two species in the genus Campsis; the other is native to China (8).

Literature and websites used: 

1. Voss E.G. 1996.  Michigan Flora Part III: Dicots Concluded. Ann Arbor, Michigan, USA: Cranbrook Institute.
2. Bailey L.H. 1963. How Plants Get Their Names. New York, New York, USA: Dover Publications.
3. Brown R.W. 1956. Composition of Scientific Words. Washington, D.C., USA: Smithsonian Institution Press.
4. Radford A.E., Ahles H.E., Bell C.R. 1968. Manual of the Vascular Flora of the Carolinas. Chapel Hill, North Carolina, USA: The University of North Carolina Press.
5. Fernald, M.L. 1950. Gray’s Manual of Botany. USA: American Book Company.
6. Stupka A. 1964. Trees, Shrubs, and Woody Vines of Great Smoky Mountains National Park. Knoxville, Tennessee, USA: The University of Tennessee Press.
7. Godfrey R.K. 1988. Trees, Shrubs, and Woody Vines of Northern Florida and Adjacent Georgia and Alabama. Athens, Georgia, USA: University of Georgia Press.
8. Cooperrider T.S. 1995. The Dicotyledoneae of Ohio Part 2. Columbus, Ohio, USA: Ohio State University Press.
9. Stephens H.A. 1969. Trees, Shrubs, and Woody Vines in Kansas. Lawrence, Kansas, USA: The Regents Press of Kansas.
10. Seymour E.L.D. 1946. The New Garden Encyclopedia. New York, New York, USA: American Book-Stratford Press, Inc.
11. Zomlefer W.B. 1994. Flowering Plant Families. Chapel Hill, North Carolina, USA: The University of North Carolina Press.
12. McGregor R.L., Barkley T.M., Brooks R.E., Schofield E.K. 1986. Flora of the Great Plains. Lawrence, Kansas, USA: The University Press of Kansas.
13. Elias, T.S. and H. Gelband 1976. Morphology and anatomy of floral and extrafloral nectaries in Campsis (Bignoniaceae). American Journal of Botany, 63 (10):1349-1353.
14. Wen, J. and R.K. Jansen 1995. Morphological and molecular comparisons of Campsis grandiflora and C. radicans (Bignoniaceae), an eastern Asian and eastern North American vicariad species pair. Plant Systematics and Evolution, 196:173-183.
15. Plants For A Future, 1996-2003. Last modified: June 2004. http://www.pfaf.org/database/plants.php?Campsis+radicans
16. USDA, NRCS. 2007. The PLANTS Database (http://plants.usda.gov, 7 November 2007). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
17. Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 8, June 2007 [accessed 7 November 2007]. http://www.mobot.org/MOBOT/research/APweb/>http://www.mobot.org/MOBOT/research/APweb/

Image Credits:   All images copyright Robyn J. Burnham except the species distribution map, derived from the Michigan Flora Online.

Primary Authors: Elizabeth Palazzola and John Bradtke, with edits and minor additions from Robyn J. Burnham

For additional information on Michigan Plant Diversity web pages please contact Robyn J. Burnham via email: rburnham“at”umich.edu