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 Bedding Lobelia is a cultivated form of L. Erinus, a native of South Africa. It is grown in hundreds of thousands in small pots, pans, or shallow boxes each year, and is a very popular plant for the margins of borders or beds, and is also extensively used for carpet bedding and other floral designs on the ground. The plants are not quite hardy, and must therefore be protected in a greenhouse or warm frame during the winter months. They are easily raised from seeds, cuttings, or division. Seeds are sown in January or February on the surface of finely prepared gritty soil in shallow boxes or pans, the seedlings being afterwards pricked out about 1 in. apart in a similar compost. The tops are often used as cuttings, being about 1 in. long, and inserted in gritty soil. Specially fine varieties are usually propagated from cuttings to keep them true. In autumn the old stock plants are placed in 3-in. or 5-in. pots, and kept close to the glass during the winter months in a genial warmth. Early in the new year, when growth becomes more vigorous, cuttings are freely produced and inserted in the way mentioned. Cuttings may be inserted in autumn as well as spring, and seeds may also be sown at the same period; but more space must be provided for the young plants thus produced.
There are several varieties, mostly blue or purple, with a few white ones; the best being: Barnard's Perpetual, Emperor William, Bluestone, Blue King, Crystal Palace: pumila, magnifica, azurea, Royal purple, all blue or purple, with a more or less conspicuous white eye; Mrs. Clibran, violet purple, with a white eye; Kathleen Mallard is a good double-flowered variety that has attracted some attention of late years. Amongst the best white Lobelias are Snowball, Mrs. Murphy, nivea, White Lady, White Pearl, White Gem, and White Perfection, all dense and compact in habit. A compact variety called Golden Queen has golden leaves and rich dark-blue flowers.
Lobelia tenuoir is a greenhouse species about 1 ft. high, having cobalt-blue flowers with a white eye. It is suitable for pots or hanging baskets, and may be raised from seeds in the same way as the Bedding Lobelia.
The best hardy herbaceous perennial Lobelias are L. cardinalis and L. fulgens (fig. 220), plants, 1-3 ft. high, with erect dark-coloured stems, lance-shaped leaves, and deep-scarlet spikes of bloom from June to September. Varieties of fulgens known as "Firefly" and "Queen Victoria", both about 5 ft. high, are particularly fine. There are now several good hybrids in cultivation. For greenhouse and bedding Lobelias see p. 182.
Fig. 220. - Lobelia fulgens.