Tree of the Month

Spring Flowering Dogwood

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The Ohio Chapter ISA continued efforts is to advance responsible tree care practices through research, technology, and education while promoting the benefits of trees. This month Tree-Of-The-Month is commonly known as the Spring Flowering Dogwoods(Cornus florida ).

The Spring Flowering Dogwood is a beautiful native tree with a four-season appeal. It has lovely flowers in spring, attractive foliage in summer and fall, colorful fruit in fall, and an exciting growth habit that provides winter interest. The native habitat of Spring Flowering Dogwood is Massachusetts to Florida, west to Texas, Mexico, and Ontario. The Spring Flowering Dogwoods' growth habit is Shrub-like or a small tree with low branches. It usually has a flat-topped crown and is more extensive than high when mature. Spring Flowering Dogwood will eventually get 30 to 40 feet tall with a greater spread.

Flowering dogwood is an essential understory species in the eastern deciduous and southern coniferous forests. This tree should be placed in the landscape where it receives partial shade but will tolerate full sun site if the soils are deep and rich.

The true flowers of the Spring Flowering Dogwood are greenish-yellow and insignificant; the four bracts are showy. The showy part of the dogwood flower is not the flower at all but the bracts.  The true flower is greenish-yellow and insignificant. The bracts are white and about 2 inches long and are effective for ten days to two weeks in April or early May. Flower buds are flat and biscuit-shaped. The four together are 3 to 4 inches across. Blossoms are effective for 10 to 14 days in April or early May. The fruit is a glossy red drupe that ripens from September to October. It can persist until mid-December. Its fruit is an important food source. Flowering dogwood is a valuable food plant for wildlife because high calcium and fat contents make it palatable. Many bird types, including songbirds, forest edge species, and upland game birds (e.g., wild turkey), consume the seeds. The eastern chipmunk, white-footed mouse, gray fox, gray squirrel, black bear, beaver, white-tailed deer, and skunk readily consume flowering dogwood seeds as well. The fruit of flowering dogwood is poisonous to humans.

The Spring Flowering Dogwood's leaves are arranged opposite on its branches, and they are simple. The leaves of Spring Flowering are 3 to 6 inches long and oval. The Spring Flowering Dogwood's leaves are bronze-green to yellow-green as they unfold, then turn dark green in summer. The fall color of the Spring Flowering Dogwood's tends to be red to reddish-purple.

The Spring Flowering Dogwood's is winter hardy to USDA Zone 5.

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Planting Requirements

Flowering dogwood prefers an acidic, well-drained soil that contains a significant amount of organic matter. It can be planted in full sun but performs best in partial shade. The tree should be mulched to keep the soil moist and cool. (Don't Pile the Mulch Against the Tree Trunk)  It does not tolerate poorly drained soils, drought, or pollution. It is hardy in Zones 5 to 9. Flowering dogwood is susceptible to borers, petal and leaf spots, and anthracnose if not correctly sited. Flowering dogwood is intolerant of extended drought periods, especially during the first year after planting.

Daily watering is necessary for the first few weeks following planting. After one month, watering should be reduced to two times per week and continue for one year. The establishment takes 6 to 12 months for each inch of trunk diameter. Larger trees benefit from irrigation during the second year.

Check with a local Ohio International Society of Arboriculture Certified Arborist for what cultivars will work in your location.

Cultivars

This tree species and its various cultivars are often sold and are available from nurseries throughout the Ohio region, and it transplants easily. There are nearly 100 cultivars of flowering dogwood. Selected cultivars by category include:

Large Flowers:

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  • 'Cloud 9' - Reaches a height of only 15 feet with a 20-foot spread. It produces many white flowers at an early age.
  • 'Junior Miss' - Large pink bracts that are resistant to spotting.
  • 'Spring Grove' - Selection from Spring Grove Cemetery in Cincinnati. Heavy producer of flowers and fruit because it sets up to three buds at each shoot tip.
  • 'Spring Time' - Large flowers and good winter bud hardiness.

Pink or red flowers:

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  • C. florida rubra - This tree is an old favorite with pink flowers and red fall foliage.
  • 'Cherokee Chief' - Has rose-red to ruby red flowers and red fall color. It reaches a height of 20 feet with a similar spread.
  • Cherokee Sunset™ - Deep pink to light red flowers and variegated yellow and green foliage. Leaves turn red in fall.
  • 'Red Beauty' - Red bract color on a compact plant.
  • 'Royal Red' - Dark red bract color to go with bright red new leaves that turn again in the fall

Variegated foliage:

  • Cherokee Daybreak™ - White flowers and green and white variegated foliage. Resistant to leaf scorch.
  • Cherokee Sunset™ - Deep pink to light red flowers and variegated yellow and green foliage. Leaves turn red in fall.
  • 'First Lady' - Leaves variegated yellow and white. Flowers have white bracts.
  • 'Welchii' - This variegation is green and white with hints of pink. Does get leaf scorch in full sun. White bracts.

Unusual growth habitdogwood2

  • 'Compacta' - Slow-growing form.
  • 'Fastigiata' - White-flowering form with upright branches.
  • 'Pendula' - Irregular, weeping habit. Flowers are white.
  • 'Pygmaea' - Slow-growing (dwarf) plants with a rounded habit. If plants bloom, they are white.
  • 'Salicifolia' - Slow-growing plant with a rounded growth habit. The leaves are narrow and "willow-like." Does not flower.
  • Rutgers Stellar series- Through the breeding efforts of Dr. Elwin Orton, Rutgers University has introduced hybrids of C. florida and C. kousa, known as Rutgers Stellar series. The hybrids start blooming after Cornus florida finishes and produce no fruit. They are highly resistant to dogwood borer and moderately to highly resistant to dogwood anthracnose. They reach an average height of 20 to 30 feet with a 15- to 25-foot spread. The hybrids are more vigorous than the parent trees with characteristics that are intermediate between the parents. The white bracts are rounded, and the flower buds are not entirely enclosed by bud scales when dormant. 
  • Aurora Dogwood (Cornus x 'Rutban' ) - This tree is erect with a uniform width. Its white flowers, which have a velvety look, become creamy white with age. The tree starts flowering 2 to 3 days after flowering dogwood has quit.
  • Constellation Dogwood (Cornus x 'Rutcan') - A low-branching tree with a uniform width, and white bracts with acute tips. It starts flowering about the same time flowering dogwood quits flowering. 
  • Celestial Dogwood (Cornus x 'Rutdan') - The white bracts overlap and have a green tinge, although they become pure white after a few days. This tree starts flowering 2 to 3 days after C. florida has stopped flowering.
  • Stardust Dogwood (Cornus x 'Rutfan') - This low, spreading tree is smaller than the other Rutgers hybrids. This tree has heavy branching to the ground, like a hedge. Its white bracts do not overlap and have acute tips. It begins to flower at the same time flowering dogwood's flowering period is ending.
  • Stellar Pink Dogwood (Cornus x 'Rutgan' ) - This low-branching tree has rounded, soft pink bracts. This tree blooms one week after flowering dogwood.
  • Ruth Ellen Dogwood (Cornus x 'Rutlan') - This tree has white flowers and a low, spreading habit like flowering dogwood. It is the first of the Stellar series to bloom, overlapping the last days of flowering dogwood.

Legal Status

Flowering dogwood is endangered in Maine, exploitable vulnerable in New York, and threatened in Vermont.

Ethnobotany

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The wood of dogwood has a high resistance to sudden shock, making it a popular choice for making golf club heads and chisel handles. It is also used for mallet heads and wedges, as it can be hammered on the ends without splitting and mushrooming out. Historically Dogwood wood was used to make hay forks, hubs of small wheels, rake teeth, and machinery bearings because it wears smoother as it is used.  Dogwood harvested in the late 19th century was used to make shuttles for the textile industry as it will not crack under strain.

The inner bark of the flowering dogwood and its roots are aromatic and contain a chemical known as alkaloid cornin. Native Americans used cornin for the treatment of malaria. Pioneers would steep( something means to soak it )dogwood bark in whiskey, then drink this to treat "the shakes."

Native Americans also used dogwood bark to derive a scarlet dye, which they used to color bald eagle feathers and porcupine quills. Dogwood tea, made from the tree's bark, was used as a substitute for quinine during the Civil War. Tea made from dogwood bark was used to induce sweating to break a fever.

In modern times, the overuse of flowering dogwood as a cut flower has threatened native stands of the tree. In the Washington, D.C. area, the Wild Flower Preservation Society placed posters on city streetcars, urging people not to cut or buy dogwood sprays. Sales dropped to such an extent that many merchants stopped marketing it.

Legend has it that dogwood was once a tall tree, but that changed when it was chosen to make the cross where Jesus Christ was crucified. The legend says the tree was ashamed and asked Christ to forgive it. Christ commanded that from that moment on, the dogwood would be slender and twisted so that it could no longer be used for a cross. The tree was designated to bear cross-shaped flowers, with a crown of thorns in the middle, and nail prints stained with red at the outer edge of each petal. Of course, the flowering dogwood is not native to the area where Christ was crucified.

Tree Selection Tips
The Ohio Chapter ISA recommends working with an ISA Certified Arborist when selecting or caring for any tree in your landscape. To better guide you on the vital plant information for the Red Buds use our friendly users guide below:

Genus Cornus
Plant Family Cornaceae
Life cycle Perennial woody
Origin Eastern United States
Habitat Partial Sun
Tree form Variable depending on the cultivar selected
Does it produce shade? Yes
Soil Flowering dogwood trees grow best in course to medium textured, well-drained soils with a pH range of 6 to 7.  They are sensitive to rapidly changing soil temperature and are most abundant in temperature-consistent woodland soils.  Although they are tolerant of seasonal dry periods, they are not tolerant of severe drought or heavy, saturated soils.  The inability to grow on extremely dry sites is attributed to their shallow root system.
Bloom season May-June very showy.
Fruit/Seed Red Drupe
Plant height 5-40 feet
Plant spread 5-40 feet
Growth rate Slow-Medium
Suitable for planting under or near electric (utility) Yes/No-Depends on cultivar chosen
Potential Concerns Susceptible to many insect and disease pests.  Most that occur are related to plant stress.


Written by Mark A. Webber BCMA, CPH, LTE,  MArborA, OCMNT, TRAQ

 

Literature Sources:

https://www.uky.edu/hort/Flowering-Dogwood (Collected on May 23, 2020)

A Natural History of Trees of Eastern and Central North America. Donald Culross Peattie

https://plants.usda.gov/plantguide/pdf/pg_cofl2.pdf (Collected on May 23, 2020)

Herrick, J.W., 1977. Iroquois medical botany. State University of New York, Albany.

Hamel, P.B., and M.U. Chiltoskey. 1975. Cherokee Plants and their uses—a 400-year history. Herald Publishing, Sylva.

Gilman, E.F., and K.C. Ruppert. 1994. Cornus florida, Fact Sheet ENH-40(http://edis.ifas.ufl.edu/MG267). Florida Cooperative Extension Service, Institute of Food and Agricultural Science, University of Florida, Gainesville.

 

Photograph sources Mark A. Webber 2020