Cornus foemina P. Mill., swamp dogwood, is primarily found along the coastal plain from eastern Virginia to central Florida, west to Louisiana and north to southeastern Missouri. It is a deciduous small tree to large shrub, growing to 15 ft in height, with multiple trunks, 4 inches in diameter. Its bark is thick and smooth, frequently furrowed with shallow ridges exposing gray inner bark. The plant’s leaves are opposite and oval-shaped, with smooth margins. Flowers are creamy white, loose, and small; they occur in flat topped clusters without showy bracts. Fruits are small, open clusters of bluish to purple drupes (fleshy, one-seeded fruits).
Range and Habitat in Illinois
Regularity: Regularly occurring
Global Range: Cornus racemosa is native to North America and occurs in dry to moist open sites from central Maine to southern Ontario and Minnesota, south to Delaware, Maryland and Virginia and west to Kentucky, Missouri, and Oklahoma (Fernald 1950). Wilson (1965) lists C. racemosa as a subspecies of C. foemina; C. foemina subsp. racemosa occurring in the northeast U.S. from Maine to Minnesota, south to Missouri and east to Virginia, C. foemina subsp. foemina occurring in the southeast from S. Carolina to Florida west to Arkansas and eastern Texas (Wilson 1965).
Distribution and adaptation
Swamp dogwood generally grows in swampy, low wetland habitats, barrier islands, and along streams, riverbanks, marshes and creeks. It is found growing along ditches on the second road back from the ocean at Emerald Isle and found to exhibit moderate salt tolerance.
Swamp dogwood is distributed throughout most of the southeast United States. For a current distribution map, please consult the Plant Profile page for this species on the PLANTS Website.
Range and Habitat in Illinois
Comments: Gray dogwood occurs in thickets and moist soil in riparian zones, roadsides, on sandy slopes and limestone ridges (Soper and Heimburger 1982).
Like most dogwoods, this species can be grown easily from seeds collected from mature, native trees and from softwood cuttings. Seeds at maturity must be either planted immediately or prechilled. Seeds sown in nursery beds should be covered with ¼ to ½ inch of soil and mulched during the winter.
Flower-Visiting Insects of Stiff Dogwood in Illinois
(the butterfly sucks nectar; this observation is from Fothergill & Vaughn)
Lycaenidae: Celastrina argiolus sn (FV)
Populations: Dogwood invasion of grasslands from swales, ravines, and woodland edges of floodplains is accelerated by vegetative reproduction and tolerance to wind, full exposure or partial shade, and dry soils (Pound and Clements 1900, Costello 1931, Steyermark 1940, Albertson and Weaver 1945, Weaver 1965, Duxbury 1982).
As density within a dogwood thicket increases, groundcover vegetation decreases and may become entirely absent (Aikman 1928, Weaver 1965). Annual weeds sometimes grow beneath dogwood (Duxbury 1982, Nyboer pers. comm. 1983), and bur oak (Quercus macrocarpa) may invade dogwood thickets (Albertson and Weaver 1945, Aikman 1928). Dogwood may persist and sometimes dominate the understory of woods (Duxbury 1982).
Life History and Behavior
Sexual reproduction: These dogwoods probably reach sexual maturity in three to four years. There is one viable seed per drupe in all four species (Stephens 1973). A complex of hybrids exists between C. drummondii, C. racemosa (C. foemina subsp. racemosa) and C. foemina (subsp. foemina). The hybrids have high pollen viability, robust growth, and fruit sometimes larger and more plentiful than that of the parent (Wilson 1965).
Seed dispersal: Seeds are dispersed by a variety of birds, including crows, vireos, redheaded woodpeckers and bluebirds (Ridley 1930), autumn through winter (Stephens 1973). Availability of perching sites may be important in dispersal. Smith (1975) included C. racemosa in his study of re-vegetation of forest openings, and found that most seeds were deposited by birds within 25 meters of the seed source, often in the shade near perching sites. About 25% of the dispersed seeds left the study area after consumption by long-distance flying birds.
Germination: Germination usually occurs in the spring following seed production and dispersal to a favorable site, but may be delayed a year due to a dormant embryo, hard pericarp (Brinkman 1974), and possible chemical inhibition by the pulp (Goodwin 1948). Mechanical and chemical scarification and stratification techniques are used commercially to stimulate germination in dogwood (Brinkman 1974). C. racemosa and C. stolonifera are described by Krefting and Roe (1949) as having "double dormancy", or requiring two periods of stratification for germination. C. stolonifera seeds that were treated first with acids then with cold stratification experienced almost 100% germination, whereas germination was much lower for those seeds receiving cold treatment only. However, seeds of both species that were twice stratified by passage through quail or pheasant gut plus cold treatment also gave relatively low percent germination. The authors suggested that this was due to a large amount of variability in the extent of scarification from the bird gizzards. Some seeds are injured or overstratified in the bird gut and some are left unscathed or understratified (Krefting and Roe 1949). Smith (1975) described C. racemosa as fruiting abundantly but having very low germinability, depending instead on vegetative reproduction to enhance its propagation. Germination tests of scarified and stratified C. drummondii seeds have shown a 25% germination in three samples after 50 days (Brinkman 1974).
Seedling establishment: Some Cornus spp. shrub seedlings are tolerant of variable light intensities, and may become established in woodland edges, within woods, or in open areas (Gatherum et al. 1963, Smith 1975). Seedlings may invade grasslands alone or with other woody plants (McClain pers. comm.).
Asexual reproduction: C. drummondii, C. racemosa, C. stolonifera and C. obliqua reproduce most successfully by vegetative growth following seedling establishment. Thickets may expand by adventitious underground shoot growth or rhizomatous growth (Stephens 1973, Wilson 1965, Smith 1975).
Molecular Biology and Genetics
Barcode data: Cornus foemina
Statistics of barcoding coverage: Cornus foemina
Public Records: 1
Specimens with Barcodes: 1
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status (e.g. threatened or endangered species, state noxious status, and wetland indicator values).
Comments: Cornus spp. are natural early successional components of many woodland ecosystems in North America. They have many adaptions that enable them to take advantage of open areas, including a large number of seeds, vigorous seedlings and rapid subsequent growth, dispersal by birds, and high tolerance to adverse conditions such as drought and shade (Smith 1975, citing Auclair and Cottam 1971). Rapid and extensive cloning by rhizomatous growth allows dogwood species to create dense thickets which crowd out desired grasses, sedges and forbs, and alter wildlife habitat. Invasion of dogwood, along with other woody species, into prairies and wetlands became more extensive mainly due to the post-settlement decline in wildfires.
Woody plant invasion of floodplains is a concern in some areas, particularly in the western U.S., where stream diversion has greatly reduced the flow in rivers. Water diversion can reduce river flow to the extent that dogwoods and other woody plants invade the floodplain, reducing river channel width and drastically altering wildlife habitat. For example, woody plant invasion, including C. drummondii, willows (Salix spp.), green ash (Fraxinus pensylvanica) and black locust (Robinia pseudoacacia), has reduced channel area of the Platte River in Nebraska by 50-85%, resulting in a loss of up to 97% of the roosting habitat for sandhill and whooping cranes and many other migratory birds (Currier 1987).
Pests and potential problems
This plant has no serious insects and diseases except occasional infestation by scale insects and leaf spot.
Cultivars, improved and selected materials (and area of origin)
None recommended. Plants are not readily available from nurseries.
Plant in moist soils in full sun to partial shade as it is tolerant to wet and/or low fertility soils. It requires little maintenance in naturalized settings. When used for massing, pruning to within a few inches of the ground every few years promotes fullness.
Relevance to Humans and Ecosystems
Uses: LANDSCAPING, Cultivated ornamental
Wildlife: Fruits are eaten by several species of birds including quail, catbirds, mockingbirds, robins, and brown thrashers.
Recreation and Beautification: Excellent landscape tree for its very attractive form and profuse white flowers. Frequently used for massing or naturalizing, screen and border.
Cornus foemina is a species of flowering plant in the Cornaceae known by the common names stiff dogwood and swamp dogwood. It is native to parts of the eastern and southeastern United States.
This plant is a large shrub or small tree up to 15 feet tall with trunks up to 4 inches wide. The bark is smooth or furrowed. The oppositely arranged, deciduous leaves are oval in shape with smooth edges. The inflorescence is a flat-topped cluster of white flowers. The fruit is a blue or purple drupe.
Names and Taxonomy
Comments: As treated here (following Kartesz, 1994 checklist), Cornus foemina excludes C. asperifolia and C. racemosa, sometimes treated as subspecies of C. foemina (ssp. microcarpa and ssp. racemosa, respectively), and includes C. stricta, sometimes recognized as distinct.
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