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 is a fine rock-garden plant, 1-2 ft high, with deeply penetrating roots, divided leaves, and masses of showy Geranium-like flowers rich purple crimson in colour. E. macradenium (or glandulosum) is only about 6 in. high, and has pale-violet or flesh-coloured flowers veined with crimson purple, the two upper petals having a dark blotch at the base. There are several other species very little known. They thrive in warm well-drained soil, and dislike cold damp spots. They are best increased by seeds sown when ripe, or by cuttings or division of the tufts with pieces of root. Trade limited.