Flowering Dogwood
Encyclopedia
Cornus florida is a species of dogwood
native to eastern North America
, from southern Maine
west to southern Ontario
, Illinois
, and eastern Kansas
, and south to northern Florida
and eastern Texas
, with a disjunct population in Nuevo León
and Veracruz
in eastern Mexico
.
Cornus
as Cornus florida L., although it is sometimes treated in a separate genus as Benthamidia florida (L.) Spach.
Two subspecies
are generally recognized:
tree
growing to 10 m (32.8 ft) high, often wider than it is tall when mature, with a trunk diameter of up to 30 cm (0.984251968503937 ft). A 10-year-old tree will stand about 5 m (16 ft) tall. The leaves
are opposite, simple, ovate, 6–13 cm long and 4–6 cm broad, with an apparently entire margin (actually very finely toothed, under a lens); they turn a rich red-brown in fall.
The flower
s are individually small and inconspicuous, with four greenish-yellow petals 4 mm long. Around 20 flowers are produced in a dense, rounded, umbel
-shaped inflorescence
, or flower-head, 1–2 cm in diameter. The flower-head is surrounded by four conspicuous large white, pink or red "petals" (actually bract
s), each bract 3 cm long and 2.5 cm broad, rounded, and often with a distinct notch at the apex. The flowers are bisexual.
When in the wild they can typically be found at the forest edge and popular on dry ridges. While most of the wild trees have white bracts, some selected cultivar
s of this tree also have pink bracts, some even almost a true red. They typically flower in early April in the southern part of their range, to late April or early May in northern and high altitude areas. The similar Kousa Dogwood
(Cornus kousa), native to Asia
, flowers about a month later.
The fruit
is a cluster of two to ten drupe
s, each 10–15 mm long and about 8 mm wide, which ripen in the late summer and the early fall to a bright red, or occasionally yellow with a rosy blush. They are an important food source for dozens of species of bird
s, which then distribute the seed
s.
in moist, acidic soil in a site with some afternoon shade
, but good morning sun. It does not do well when exposed to intense heat sources such as adjacent parking lots or air conditioning
compressors
. It also has a low salinity tolerance. The hardiness zone for flowering dogwood is 5-9 and the preferred PH is between 6.0-7.0. In urban and suburban settings, care should be taken not to inflict mower damage on the trunk or roots, as this increases the tree’s susceptibility to disease and pest pressure.
In regions where dogwood anthracnose is a problem, homeowners and public land managers are encouraged to know the symptoms and inspect trees frequently. The selection of healthy, disease-free planting stock is essential and transplanting trees from the forest should be avoided. Sites should be selected for reasonably well-drained, fertile soils; full sun is recommended in high-hazard areas (such as stream or pond banks). New plantings should be mulched to a depth of 2 to 4 in (5.1 to 10.2 cm), avoiding the stem. Dead wood and leaves should be pruned and completely removed and destroyed yearly. Plants should be watered weekly during droughts, with watering done in the morning, avoiding wetting the foliage. Registered fungicides can be applied when necessary, according to manufacturers instructions and advice of local Extension Service.
Flowering dogwood is grown widely throughout mid-temperate North America. In the eastern part of the continent, it is cultivated as far north as Toronto and south to central Florida
. Farther west, places of cultivation include Boulder
, Sacramento
and Vancouver. It is also sold in other temperate parts of the world, including Sydney
, Australia
.
Selected cultivars
Flowering dogwood demonstrates gametophytic self-incompatibility, meaning that the plants can’t self-fertilize. This is important for breeding programs as it means that it is not necessary to emasculate (remove the anthers from) C. florida flowers before making controlled cross-pollinations. These pollinations should be repeated every other day, as the flowers must be cross-pollinated within one or two days of opening for pollinations to be effective.
Softwood cuttings taken in late spring or early summer from new growth can be rooted under mist if treated with 8,000 to 10,000 ppm indole-3-butyric acid
(IBA). In cold climates, potted cuttings must be kept in heated cold frames or polyhouse
s the following winter to maintain temperatures between 0 and 7°C. Although rooting success can be as high as 50-85%, this technique is not commonly used by commercial growers. Rather, selected cultivars are generally propagated by T-budding
in late summer or by whip grafting
in the greenhouse in winter onto seedling rootstock.
Micropropagation
of flowering dogwood is now used in breeding programs aiming to incorporate resistance to dogwood anthracnose and powdery mildew into horticulturally and economically important cultivars. Nodal (axillary bud
) sections are established in a culture of Woody Plant Medium (WPM) amended with 4.4 μM 6-Benzyladenine (BA) to promote shoot growth. Rooting of up to 83% can be obtained when 5-7 week-old microshoots are then transferred to WPM amended with 4.9 μM IBA.
substitute. The hard, dense wood has been used for products such as golf club heads, mallets, wooden rake teeth, tool handles, jeweler’s boxes and butcher’s blocks.
Dogwood
The genus Cornus is a group of about 30-60 species of woody plants in the family Cornaceae, commonly known as dogwoods. Most dogwoods are deciduous trees or shrubs, but a few species are nearly herbaceous perennial subshrubs, and a few of the woody species are evergreen...
native to eastern North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, from southern Maine
Maine
Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...
west to southern Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
, and eastern Kansas
Kansas
Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...
, and south to northern Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
and eastern Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, with a disjunct population in Nuevo León
Nuevo León
Nuevo León It is located in Northeastern Mexico. It is bordered by the states of Tamaulipas to the north and east, San Luis Potosí to the south, and Coahuila to the west. To the north, Nuevo León has a 15 kilometer stretch of the U.S.-Mexico border adjacent to the U.S...
and Veracruz
Veracruz
Veracruz, formally Veracruz de Ignacio de la Llave officially Estado Libre y Soberano de Veracruz de Ignacio de la Llave , is one of the 31 states that, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided in 212 municipalities and its capital city is...
in eastern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
.
Classification
The flowering dogwood is usually included in the dogwood genusGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Cornus
Dogwood
The genus Cornus is a group of about 30-60 species of woody plants in the family Cornaceae, commonly known as dogwoods. Most dogwoods are deciduous trees or shrubs, but a few species are nearly herbaceous perennial subshrubs, and a few of the woody species are evergreen...
as Cornus florida L., although it is sometimes treated in a separate genus as Benthamidia florida (L.) Spach.
Two subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
are generally recognized:
- Cornus florida subsp. florida. Eastern United StatesUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
, southeastern CanadaCanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
(OntarioOntarioOntario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
). - Cornus florida subsp. urbiniana (Rose) Rickett (syn. Cornus urbiniana Rose). Eastern MexicoMexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
(Nuevo LeónNuevo LeónNuevo León It is located in Northeastern Mexico. It is bordered by the states of Tamaulipas to the north and east, San Luis Potosí to the south, and Coahuila to the west. To the north, Nuevo León has a 15 kilometer stretch of the U.S.-Mexico border adjacent to the U.S...
, VeracruzVeracruzVeracruz, formally Veracruz de Ignacio de la Llave officially Estado Libre y Soberano de Veracruz de Ignacio de la Llave , is one of the 31 states that, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided in 212 municipalities and its capital city is...
).
Description
Flowering dogwood is a small deciduousDeciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
growing to 10 m (32.8 ft) high, often wider than it is tall when mature, with a trunk diameter of up to 30 cm (0.984251968503937 ft). A 10-year-old tree will stand about 5 m (16 ft) tall. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are opposite, simple, ovate, 6–13 cm long and 4–6 cm broad, with an apparently entire margin (actually very finely toothed, under a lens); they turn a rich red-brown in fall.
The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are individually small and inconspicuous, with four greenish-yellow petals 4 mm long. Around 20 flowers are produced in a dense, rounded, umbel
Umbel
An umbel is an inflorescence which consists of a number of short flower stalks which are equal in length and spread from a common point, somewhat like umbrella ribs....
-shaped inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
, or flower-head, 1–2 cm in diameter. The flower-head is surrounded by four conspicuous large white, pink or red "petals" (actually bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s), each bract 3 cm long and 2.5 cm broad, rounded, and often with a distinct notch at the apex. The flowers are bisexual.
When in the wild they can typically be found at the forest edge and popular on dry ridges. While most of the wild trees have white bracts, some selected cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s of this tree also have pink bracts, some even almost a true red. They typically flower in early April in the southern part of their range, to late April or early May in northern and high altitude areas. The similar Kousa Dogwood
Kousa Dogwood
The Kousa Dogwood is a small deciduous tree 8–12 m tall, native to eastern Asia. Like most dogwoods, it has opposite, simple leaves, which are 4–10 cm long. The tree is extremely showy when in bloom, but what appear to be four petaled white flowers are actually bracts spread open below the...
(Cornus kousa), native to Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, flowers about a month later.
The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
is a cluster of two to ten drupe
Drupe
In botany, a drupe is a fruit in which an outer fleshy part surrounds a shell of hardened endocarp with a seed inside. These fruits develop from a single carpel, and mostly from flowers with superior ovaries...
s, each 10–15 mm long and about 8 mm wide, which ripen in the late summer and the early fall to a bright red, or occasionally yellow with a rosy blush. They are an important food source for dozens of species of bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, which then distribute the seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s.
Cultivation
Flowering Dogwood does best horticulturallyHorticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
in moist, acidic soil in a site with some afternoon shade
Shade
Shade is the blocking of sunlight by any object, and also the shadow created by that object. Shade also consists of the colors grey, black, white, etc...
, but good morning sun. It does not do well when exposed to intense heat sources such as adjacent parking lots or air conditioning
Air conditioning
An air conditioner is a home appliance, system, or mechanism designed to dehumidify and extract heat from an area. The cooling is done using a simple refrigeration cycle...
compressors
Gas compressor
A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume.Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. As gases are compressible, the compressor also reduces the volume of a gas...
. It also has a low salinity tolerance. The hardiness zone for flowering dogwood is 5-9 and the preferred PH is between 6.0-7.0. In urban and suburban settings, care should be taken not to inflict mower damage on the trunk or roots, as this increases the tree’s susceptibility to disease and pest pressure.
In regions where dogwood anthracnose is a problem, homeowners and public land managers are encouraged to know the symptoms and inspect trees frequently. The selection of healthy, disease-free planting stock is essential and transplanting trees from the forest should be avoided. Sites should be selected for reasonably well-drained, fertile soils; full sun is recommended in high-hazard areas (such as stream or pond banks). New plantings should be mulched to a depth of 2 to 4 in (5.1 to 10.2 cm), avoiding the stem. Dead wood and leaves should be pruned and completely removed and destroyed yearly. Plants should be watered weekly during droughts, with watering done in the morning, avoiding wetting the foliage. Registered fungicides can be applied when necessary, according to manufacturers instructions and advice of local Extension Service.
Flowering dogwood is grown widely throughout mid-temperate North America. In the eastern part of the continent, it is cultivated as far north as Toronto and south to central Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. Farther west, places of cultivation include Boulder
Boulder, Colorado
Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of...
, Sacramento
Sacramento, California
Sacramento is the capital city of the U.S. state of California and the county seat of Sacramento County. It is located at the confluence of the Sacramento River and the American River in the northern portion of California's expansive Central Valley. With a population of 466,488 at the 2010 census,...
and Vancouver. It is also sold in other temperate parts of the world, including Sydney
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
Selected cultivars
- ‘Amerika Touch-O-Pink’ – large bracts, tinged pink; large leaves; good disease resistance.
- ‘Appalachian Spring’ – large white bracts; red fall foliage; resistant to dogwood anthracnose.
- 'Autumn Gold' - white bracts; yellow fall color.
- 'Barton' - large white bracts; blooms at early age; resistant to stem canker and powdery mildew.
- 'Bay Beauty' - double white bracts; resists heat and drought; good for Deep South.
- 'Cherokee Daybreak' - white bract; vigorous grower with variegated leaves.
- 'Cherokee Chief' - red bracts; red new growth.
- 'Cherokee Brave' - Even redder than 'Cherokee Chief', smaller bracts but dark red color; consistently resistant to powdery mildew.
- 'Cherokee Princess' - vigorous white bracts, industry standard for white flowers.
- 'Cherokee Sunset' - purplish-red bracts; variegated foliage.
- 'Gulf Coast Pink' - best pink flowering dogwood in Florida – northern part only.
- 'Hohman's Gold' - white bracts; variegated foliage.
- ‘Jean’s Appalachian Snow’ – large, overlapping white bracts w/ green flowers; very resistant to powdery mildew.
- ‘Karen’s Appalachian Blush’ – delicate white bracts edged in pink; some powdery mildew resistance.
- ‘Kay’s Appalachian Mist’ – stiff, creamy white bracts; red fall foliage; good resistance to powdery mildew.
- 'Plena' - double white bracts; spot anthracnose-resistant.
- 'Purple Glory' - red bracts; purple foliage; spot anthracnose-resistant but susceptible to stem canker.
- 'Weaver White' - large white blooms; large leaves; candelabra shape; good in north-central Florida.
Propagation
Cornus florida is easily propagated by seeds, which are sown in the fall into prepared rows of sawdust or sand, and emerge in the spring. Germination rates for good clean seed should be near 100% if seed dormancy is first overcome by cold stratification treatments for 90 to 120 days at 4 °C (39.2 °F).Flowering dogwood demonstrates gametophytic self-incompatibility, meaning that the plants can’t self-fertilize. This is important for breeding programs as it means that it is not necessary to emasculate (remove the anthers from) C. florida flowers before making controlled cross-pollinations. These pollinations should be repeated every other day, as the flowers must be cross-pollinated within one or two days of opening for pollinations to be effective.
Softwood cuttings taken in late spring or early summer from new growth can be rooted under mist if treated with 8,000 to 10,000 ppm indole-3-butyric acid
Indole-3-butyric acid
Indole-3-butyric acid is a white to light-yellow crystalline solid, with the molecular formula C12H13NO2. It melts at 125 °C in atmospheric pressure and decomposes before boiling.-Plant hormone:...
(IBA). In cold climates, potted cuttings must be kept in heated cold frames or polyhouse
Polyhouse
Polyhouse is a protective shade made up of polythene used for growing high value agricultural products.It is semi-circular, square or elongated in shape. Temperature, humidity, ventilation of air are controlled by the equipments fixed in the polyhouse....
s the following winter to maintain temperatures between 0 and 7°C. Although rooting success can be as high as 50-85%, this technique is not commonly used by commercial growers. Rather, selected cultivars are generally propagated by T-budding
Shield budding
Shield budding is a technique of grafting to change varieties of fruit trees. Typically used in fruit tree propagation, it can also be used for many other kinds of nursery stock. An extremely sharp knife is necessary; specialty budding knives are on the market...
in late summer or by whip grafting
Grafting
Grafting is a horticultural technique whereby tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. This vascular joining is called inosculation...
in the greenhouse in winter onto seedling rootstock.
Micropropagation
Micropropagation
Micropropagation is the practice of rapidly multiplying stock plant material to produce a large number of progeny plants, using modern plant tissue culture methods....
of flowering dogwood is now used in breeding programs aiming to incorporate resistance to dogwood anthracnose and powdery mildew into horticulturally and economically important cultivars. Nodal (axillary bud
Axillary bud
The axillary bud is an embryonic shoot which lies at the junction of the stem and petiole of a plant.As the apical meristem grows and forms leaves, a region of meristematic cells are left behind at the node between the stem and the leaf. These axillary buds are usually dormant, inibited by auxin...
) sections are established in a culture of Woody Plant Medium (WPM) amended with 4.4 μM 6-Benzyladenine (BA) to promote shoot growth. Rooting of up to 83% can be obtained when 5-7 week-old microshoots are then transferred to WPM amended with 4.9 μM IBA.
Historical uses
Other old names now rarely used include American Dogwood, Florida Dogwood, Indian Arrowwood, Cornelian Tree, White Cornel, False Box, and False Boxwood. This species has in the past been used in the production of inks, scarlet dyes, and as a quinineQuinine
Quinine is a natural white crystalline alkaloid having antipyretic , antimalarial, analgesic , anti-inflammatory properties and a bitter taste. It is a stereoisomer of quinidine which, unlike quinine, is an anti-arrhythmic...
substitute. The hard, dense wood has been used for products such as golf club heads, mallets, wooden rake teeth, tool handles, jeweler’s boxes and butcher’s blocks.
External links
- Germplasm Resources Information Network: Cornus florida
- NRCS: USDA Plants Profile: Cornus florida
- Missouriplants: Cornus florida
- Bioimages: Cornus florida
- Floridata: Cornus florida
- Univ. of Connecticut Plant Database: Cornus florida
- US Forest Service: Cornus florida
- UC IPM Online: Dogwood pest management
- Dogwood Borer
- Dogwood Anthracnose
- Foliar Diseases of Dogwood
- Interactive Distribution Map of Cornus florida