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 Common Bluebell grows freely in any good garden soil, and its spikes of blooms sell during the early summer months. Besides the ordinary bluish-purple form, there are others having pure-white and rose-coloured flowers. For market purposes a fairly large number of bulbs might be planted between rows of fruit trees in the same way as Daffodils, and once planted may be left to look after themselves. Bulbs of the ordinary variety may be obtained for 10s. or so per 1000.
The Spanish Bluebell is Scilla hispanica or campanulata. It flowers in May, and has fine spikes 12-18 in. high of large bell-shaped flowers. There are blue, white, and rose-coloured forms, but the white one is best for market.