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 pretty little Japanese rock plant, 2-4 in. high, with roundish leaves which turn to a dark purple in winter, and pairs of drooping bell-shaped flowers from March to June, the petals being cut into thread-like fringes. It likes a peaty soil and sheltered spots, and is increased from seeds and by careful division.