Blossom dogwood
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Inflorescence of the dogwood ( Cornus florida ) |
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The flower dogwood ( Cornus florida ), also known as the American flower dogwood , is a species of the dogwood genus . It originates from eastern North America and is occasionally used as an ornamental plant in the temperate regions almost worldwide because of its showy inflorescences .
description
Vegetative characteristics
The flowering dogwood grows in its natural range as a shrub or small tree , which can reach heights of up to 12 meters, in the undergrowth or on the edge of forests. At the northern edge of its distribution area and mostly also in culture it remains smaller and grows shrub-like. The crown is spread out to round, the side branches often grow almost horizontally reaching out from the trunk. The bark of the twigs is initially greenish with a reddish tint on the sunny side, later it turns gray, a cracked bark develops on thicker trunks. The winter buds can be clearly distinguished in leaf and inflorescence buds , the latter are broadly onion-shaped.
The intensive root system remains flat under the surface of the soil, it is sensitive to compaction, flooding and mechanical damage. Runners are not formed.
The constantly against arranged on the branches leaves are divided in leaf blade and leaf stem. The simple leaf blade is 7 to 12 centimeters long and shaped like many other dogwoods : oval, with entire margins and next to the midrib with five to six forwardly curved lateral nerves. When they shoot they are yellowish green, in summer they are dull green, the autumn colors are bright orange-red to purple. The fallen leaves decompose extremely quickly.
Generative characteristics
In spring, a little before or at the same time as the leaf shoots, the flowers unfold. About twenty are combined to form small, spherical, umbellate inflorescences , each umbel is framed by four white, rarely pink bracts . The bracts can already be recognized by the bud in winter, about 5 to 10 centimeters long and indented at the tip. The bracts often hang together with the tips for a long time when they unfold.
The elongated berries turn red in autumn . In contrast to the Asian dogwoods, the individual fruits of the inflorescence do not grow together to form a fruit cluster . The berries contain a core that germinates the following spring, rarely after two winters. The fruits are eaten by numerous birds and mammals, which thus ensure the spread ( zoochory ).
Some sources say that the fruits are poisonous to humans, others call them edible.
Chromosome number
The number of chromosomes is 2n = 22.
Occurrence
Cornus florida is native to eastern North America, from the extreme south of Canada to northern Florida, from the Atlantic coast to eastern Texas and Oklahoma. The variety Cornus florida var. Urbiniana is known from eastern Mexico.
The flowering dogwood avoids dry and waterlogging locations, it grows in the undergrowth or on the edge of deciduous and pine forests. Cornus florida usually thrives on well drained, humus rich soils with a slightly acidic to neutral pH value .
Diseases
The fungus Discula destructiva , detected in North America since 1976, causes the so-called leaf tan (anthracnose), which leads to the death of the plant. Cornus florida has been significantly decimated in its area of distribution. Damp locations are particularly affected. Cornus florida can also be attacked by the European white berry mistletoe , so it is not mistletoe-proof like many other North American woody species with European relatives that are now mistletoe-proof.
Taxonomy
The first publication of Cornus florida was done by Carl von Linné . The specific epithet florida does not refer to the US state Florida, but to the large bracts .
use
Within the natural range, the flower dogwood is used for near-natural plantings and hedges and is a widespread ornamental wood; it is the " state flower " of the US states Virginia and Missouri . Due to the dense, wide sweeping root system to inhibit the erosion of soils .
Because of the conspicuous bracts and the red autumn color, the flowering dogwood is cultivated as an ornamental shrub . It places high demands on the soil, needs an even water supply and high humidity. Even under good conditions, it grows quite slowly with an annual increase of ten to 15 centimeters. That is why it is best suited as a solitary shrub in particularly well-kept locations.
Although it can withstand shade, a location that is temporarily sunny is more favorable for abundant flowering. Good soil and air humidity is important in full sun locations.
There are numerous varieties, especially those with particularly large or pink bracts. Hanging forms, varieties with variegated leaves or with yellow fruits are also rarely found. Some varieties have more than four bracts.
- 'Cherokee Chief' - Intense pink bracts
- 'Cloud Nine' - Large, white bracts
- 'Rubra' - under this name, various types with more or less intensely pink bracts are commercially available
- 'Eddie's White Wonder' - A hybrid between Cornus florida and the Pacific dogwood ( Cornus nuttallii )
The horticultural propagation can take place via seeds , which germinate well after three months of cold stratification . Varieties have to be propagated by cuttings or grafting , so that plants ready for sale can be achieved faster.
Individual evidence
- ↑ American Forest Association (Ed.): National Register of Big Trees , online version ( Memento of the original from September 26, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b J. Vimmerstedt: flowering dogwood (Cornus florida L.). In: Silvics of forest trees of the United States. Pp. 162-166. US Department of Agriculture (Ed.) 1965.
- ↑ The flower dogwood in the Halle Botanical Garden
- ^ Russell M. Burns: Silvics of North America: Conifers . US Department of Agriculture, Forest Service, 1990 ( google.de [accessed January 26, 2020]).
- ↑ Cornus florida at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
- ↑ Distribution map (PDF; 746 kB)
- ↑ TU Munich: Leaf tan (anthracnose) in the flower dogwood ( memento of the original from January 3, 2015 in the web archive archive.today ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ J. Hillier, J. Kelly (Ed.): Trees and bushes . P. 240. Thalacker 1997.
- ^ D. Mac Cárthaigh, W. Spethmann, (Ed.): Krüssmanns Gehölzvermehrung. Parey 2000, p. 243.
