This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
An ornamental deciduous Syrian shrub, 6-8 ft. high, with lobed and toothed leaves, and Mallow-like purple flowers in August and September, with a crimson spot at the base of the petals. There are white, yellow, purple, rose, violet varieties, one of the best being coelestis. There are also double forms. Increased by cuttings or layers. Warm sheltered spots are best.