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 geranium proper must not be confused with the florist's Geranium, which is more correctly known as the "Zonal" Pelargonium (which see). The Geraniums are mostly hardy herbaceous perennials, with divided leaves, and bluish or purple flowers. They flourish in any garden soil, and may be increased by seeds or division. The trade in them is restricted to nurserymen. The best kinds are: armenum, 2 ft., bright purple; Endressi, 1 ft., pale rose purple; ibericum, 2 ft., violet blue; pratense, 2-3 ft., blue and violet, with a fine double form; Robertianum, 1 ft., the "Herb Robert", bright crimson; macrorhizon, 1 ft., bright purple; sanguineum, 1-2 ft., crimson, or blood red, with a variety lancastriense, having pink purple-veined flowers; grandiflorum, 9 in., a lovely Himalayan plant, with violet purple flowers; Grevilleanum, 3 ft., pale violet, very fine; and anemonoefolium or Lowi, 2 ft., rose purple, with large leaves that assume beautiful green, gold, and reddish tints in autumn.