This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
The hardy section of this tribe comprises few genera but many species. A good many of them were old familiar plants in gardens; but they have for many years been lost sight of, their quiet unobtrusive style being scarcely tolerated while the rage for colour was rampant. Recently, however, some species of Sempervivum with rigid geometric aspect, and Sedums with close carpet-like growth or glaucous leaves, and several Echeverias, along with other plants of succulent or peculiar foliage, have been used to produce novel and pretty results in flower-gardening. It is a step in the right direction, and will serve to relieve the present style of flower-gardening from the ban of obtrusive monotony that has been laid on it for some time. Very few, if any, of the hardy Crassulaceae are distinguished by brilliant colours or showy qualities of any kind; their peculiar recommendations are rather that they abound in soft tints of flower and foliage, and great variety of form and aspect - they are, in fact, generally humble quiet objects, but attractive and pleasing in a high degree.
For the most part they are mountain rock-plants, generally affecting dry habitats where little else will grow but themselves; they are therefore naturally well adapted for ornamenting dry rock work, for planting in thin gravelly soil, on dry exposed banks, and for draping stumps and stones and old walls or ruins with a varied mantle of interesting vegetation. Many of them are excellent border-plants; and, as already alluded to above, some are likely to become popular for many uses in the flower-gardens in bedding out. They are plants of the easiest culture, flourishing abundantly in almost any soil but those that are excessively wet; but special requirements of species for peculiar purposes will be noticed afterwards in the proper place. All may be propagated by division - that method is unmistakably suggested to even the casual observer by the Sempervivums generally, which divide themselves, more or less freely, annually; but in nearly every case propagation in this tribe is the most simple matter, whether by division or cuttings.