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.
Distinct-looking shrubs or small trees often covered with silvery scales. They flourish in ordinary good soil, and are increased by seeds, cuttings, layers, or grafting. The best-known kinds are angustifolia, argentea (the Missouri Silver Tree), glabra, hortensis, longipes, macro-phylla, pungens, and umbellata. They make fine dense bushes, the variegated forms of pungens being particularly attractive.