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.
A well-known and charming native annual or biennial, 2-3 ft. high, with narrow downy leaves, and heads of bright-blue flowers in summer and autumn. It is an excellent plant for cut flower, and a trade is also done in the plants in spring. There are several varieties, including Emperor William, deep blue, flore pleno, double, as well as rose, purple, and white varieties. Seeds may be sown in autumn to produce good plants for sale in spring, and also for early flower. Seeds are also sown in gentle heat in spring, or in shallow drills in the open air.