Cornus nuttallii
Inflorescence of Nuttall's flowering dogwood (Cornus nuttallii )
The Nuttall's flowering dogwood is a species of the genus of dogwood (Cornus ). It grows in moist coniferous forests on the Pacific coast of North America. Sometimes called Pacific Dogwood blooms, it is occasionally cultivated as ornamental tree because of its decorative inflorescences.
The botanical name refers to Thomas Nuttall, who collected this species on the Columbia River and gave it to Audubon, who mentioned in his book Birds of America.
Description
The Nuttall's flowering dogwood is a small deciduous tree. The largest specimens can reach a height of up to twenty, sometimes up to thirty meters. He develops a deep root system with a taproot. The crown is far more cross with horizontal side branches are in bright places, in the shadow also narrow and irregular. Young twigs are gray, dark to bark on older branches and smooth, only thicker stems, a cracked bark developed.
The opposite, oval leaves are dark green on top, the underside is lighter in color and slightly gray. The leaf veins are typical of dogwood, bent toward the blade tip. In the autumn the leaves turn red before falling.
The inflorescence consists of numerous tiny flowers which are summarized in a spherical umbel. Note the bracts surrounding the inflorescence: usually six, white and pointed, to seven inches long. The number varies from four to seven, and the shape is quite variable, often come to an inflorescence at the same time be very narrow to broad overlapping bracts, sometimes dyed slightly pink. The pointed ends distinguish this from the inflorescence flower Dogwood with indented bracts. In addition to the main bloom in late spring often appear again in the fall more inflorescences.
The fruits that form are small, red berries that are tightly packed together. They each contain a nucleus and are eaten by birds and small mammals, which thus provide for the dissemination ( Zoochorie ).
Dissemination
The species native to western North America, from the extreme south-west of Canada to California. In the south of its range to higher altitudes are populated than in the north, to the east the spread is limited by the increasing drought. Only in northern Idaho, there are isolated populations at a greater distance from the Pacific Ocean.
The vegetation in these areas consists mainly of coniferous forests: Typical representatives include the Western Hemlock, Douglas fir, various firs and pines, or those giant trees as the coast redwood. These conifers are all high, often more than fifty meters, so that Nuttall's flowering dogwood grows in the understory or on the edge. Even in the shade, it can still thrive, flowers there but sparse. We often find this tree in streams because it tolerates occasional flooding. The preferred soils are permeable, humus rich, nutrient- rich, slightly acidic and well supplied with water.
The fungus Discula destructiva detected since 1976 in North America, causing the so-called leaf blight ( anthracnose ), which leads to the death of the plant, the species has been significantly depleted in their area of distribution. Damp locations, are particularly affected.
Use
Because of the showy bracts and the red autumn coloring Nuttall is cultivated as an ornamental flowering dogwood shrub. He places high demands on the soil, requires a steady water supply and a high humidity. Even under good conditions it grows in Central Europe quite slowly, with an annual growth of 15 to twenty centimeters. Therefore, he is best suited as a specimen shrub in particularly well-kept sites. Though he endures shadow, a temporary sunniest location is more favorable for a rich bloom. At full sun a good soil and humidity is important.
In trade, the varieties ' Ascona ', ' Monarch ' and ' North Star' with wide bracts are larger and more likely to find and 'Gold Spot' yellowish mottled leaves.
' Eddie's White Wonder ' is a hybrid between Cornus florida and C. nuttallii. Hybrids with the Asian Blossom Dogwood (Cornus kousa ) are also possible and are grown in the United States to obtain Garden plants that are resistant to leaf blight ( anthracnose ).