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.
This pretty-flowered and popular genus embraces hardy plants, several species of which are natives of Britain, including the Wood Forget-me-not (M. sylvatica) and the Marsh Forget-me-not (M. palustris). For present purposes, however, two outstanding types merit notice: those suited for pot culture and those best adapted for bedding. Of the first named, Star of Love, Bouquet, Gem, and Perfection are the best, and of the latter, dissitiflora and Royal Blue. The former set embraces rose, white, and blue; the latter, light and dark shades.
The chief value of Forget-me-nots lies in growing them in pots for market work or as cut flowers. In each case, if early produced, they find a ready sale. Royal Blue, and dissitiflora in blue and white, are invaluable for cutting or for bedding out, and are worth growing in quantity.
Their cultivation is very simple. Sow seeds in May or June and transplant the seedlings early to cool, partially shaded quarters, finally potting those desired. The plants may be readily increased by cuttings or by division, the latter operation being best done in early spring when the flowering is past. As an acre of Forget-me-nots will yield about 80,000 plants at 6 in. apart, or, allowing for footpaths, about 65,000, they may be looked upon as a fairly remunerative crop. Five thousand dozen plants at 6d. per dozen would yield a gross return of £125, thus allowing enough for the grower who is fortunate enough to obtain a good and ready sale.