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.
There are several species of Tobacco grown largely for sale in spring and early summer. The most popular, however, are N. affinis, the white sweet-scented species, 2-3 ft. high, and the rose, pink, and purple-flowered hybrids under the name of Sanderae, which, have been raised by crossing N. affinis with N. Forgeti - the latter a Peruvian red-flowered species. N. sylvestris has large leaves and dense clusters of long-tubed sweet-scented flowers which remain open all day, unlike those of N. affinis, which are best in the evening. A fine Tobacco, having the large leaves marbled and blotched with creamy white and pale yellow, is N. tomentosa, better known as colossea variegata. It is an excellent plant for beds and borders, and is best raised from cuttings in spring inserted in sandy soil with bottom heat, but with the tops uncovered. N. glauca, with yellow flowers, N. macrophylla or gigantea, with pale-red flowers, N. suaveolens, white, and the Common Tobacco (N. Tabacum), with rosy flowers, are all worth attention. They are easily raised from seeds in gentle heat. In the milder parts of the kingdom, and especially in parts of Ireland, attempts have been made to grow N. Tabacum as an article of commerce. There is no doubt it could be so grown, and very fair profits might be made. The percentage of nicotine would probably be greater than in the real Havana Tobacco, but this would make the leaves more valuable from an insecticide point of view.