This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
The Marguerite, or Paris Daisy, is a form of Chrysan-themum (or Pyrethrum) frutescens, and grows wild as a shrubby perennial in the Canary Islands. It may be raised from seeds sown in February and March in the same way as Petunias, but market growers greatly prefer to raise their stock from cuttings. There are now some millions of plants raised in this way every year, and they find an ever-ready sale, varying from 6s. to 18s. per dozen for plants in 5-in. pots, according to circumstances.
Cuttings are taken in early spring, and also in autumn, from stock plants which have been cut down to encourage a good crop of clean young shoots. Those rooted in spring are useful for early winter work, and those in autumn are largely used for summer bedding. Indeed, young autumn-struck plants are sold in great numbers to the trade early in the year by growers who make a speciality of raising a stock for those who have not the convenience for doing so, and good sturdy little plants may be had for about 5s. to 8s. per hundred. The white variety is by far the most popular for market work, one reason, perhaps, being that it does not so easily fall a prey as the yellow-flowered variety to the Leaf-miner that tunnels in the leaves and utterly spoils the appearance of the plants.
Once well rooted in pots, pans, or boxes of gritty soil, Marguerites are potted up singly into 60s in a soil that is rather poor than rich, so as not to engender excessive stem growth at the expense of the flowers. The plants are pricked out two or three times during the period of growth, and are eventually shifted into 5-in. pots when large enough. During the summer months they are stood in the open air, and the most important as well as the most arduous work is to keep them watered thoroughly during the hot weather. Sometimes the plants require watering three and four times a day, and even then half the water applied is wasted in the sense that it does not wet the soil in the pots, but the ground on which they are standing.
For early flowers in winter, batches of plants are taken under glass, but before severe frosts come the whole crop must be placed in shelter. Houses with plenty of light, a free circulation of air, and a temperature not lower than 40° F. by night will suit Marguerites very well, and will keep them free from the leaf maggot. This pest surely appears if the temperature becomes too high, say up to 60° or 70° F., and will soon ruin a crop. To check it an eggcupful of paraffin or kerosene to 3 gal. of warm water and a little soft soap should be sprayed occasionally over the plants while the leaves are still green and healthy. Once, however, the maggot is between the two skins of the leaves, insecticides of any kind are useless, and the only remedy is to pick off the injured leaves by hand, and have them burned at once.
Besides the white- and yellow-flowered varieties with single flower heads there is now a beautiful double-flowered one called Mrs. F. Sander. This has pure-white flowers about 4 in. across, with a ring of strap-shaped florets surrounding a close bunch of quilled florets in the centre. It is a charming variety, and is excellent for cut-flower purposes. Flowers of the yellow Marguerite are imported in large quantities, and find a ready sale in April and May.