The Encyclopedia Americana (1920)/Carnation

CARNATION, a half-hardy perennial herb (Dianthus caryophyllus) of the family Silenaceæ, a native of southern Europe. It has more or less erect stems with enlarged joints, linear opposite leaves covered with a bloom, and solitary, variously colored, terminal, perfumed flowers, which naturally appear during summer, but which are produced artificially in certain varieties throughout the year. The plant has been in cultivation for its flowers for more than 2,000 years, but not until the early years of the 16th century did its flowers become greatly differentiated from their original flesh tint, which suggested the popular name (Latin carnatio). So numerous became the varieties that systems of classification were adopted. The popular European system of today is: (1) &ldquo;Selfs,&rdquo; flowers of one color; (2) &ldquo;flakes,&rdquo; flowers with yellow or white ground and striped with either rose, scarlet or purple; (3) &ldquo;bizarres,&rdquo; resembling flakes except that they are striped with more than one color; (4) &ldquo;picotees,&rdquo; with white or yellow petals margined with red, etc. The summer-blooming carnations which suggested this classification are little grown in America, but are very popular in Europe. They seem to demand a moist, cool climate. The group most cultivated in America, known as perpetual-flowering tree, or monthly carnations, originated in France about 1840 as the result of crossing and selection. The first of these varieties imported into America is said to have arrived in 1856. since when the growing of carnations under glass as a crop has developed. The extent of the industry is very great and is steadily growing. According to the census report of 1900 the value of the carnation crop in 1899 was about $4,000,000, produced in about 9,000 American commercial greenhouses.

Propagation of the monthly carnations is usually effected by means of cuttings of young stems. When well rooted they are potted in good soil and kept until late spring, when they are transplanted to the open ground or to the benches where they are to blossom. A winter temperature ranging between 50° and 55° at night and preferably only 10° higher during the day is desirable. At the end of the winter they are thrown away.

The most common insect pests of the carnation are the red spider and the green aphis. The red spider thrives best in dry atmosphere, and is most easily controlled by syringing with water and evaporating (not burning) sulphur in the greenhouse once a week for about five weeks, when the insects become troublesome. The green fly or green aphis seems to thrive under any ordinary conditions. It is usually fought with tobacco fumes of various extracts of tobacco. Three fungous diseases are often troublesome, rust (Uromyces caryophyllinus), spot, or blight (Septoria dianthi), and anthracnose (Volutella Sp.). These are largely prevented by judicious management, and when they occur may be controlled by destroying diseased plants and by spraying with Bordeaux mixture (See ). Rust appears on the stems and leaves as blisters which break and expose brown spores. Spot consists of brown dots with black centres where the spores are borne. Anthracnose is characterized by grayish-brown spots. (Bailey, &lsquo;Cyclopedia of American Horticulture,&rsquo; New York 1914). Thirty-seven acres of land are devoted to the raising of carnations at a nursery in Los Angeles, Cal. Nine greenhouses, each 200 feet long and 15 feet wide, together holding 35 tons of glass, are used to raise the young plants.