This section is from the book "Commercial Gardening Vol1", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
The simplest method of raising these is from seeds. These are collected when ripe in autumn and carefully stored until the spring. In some cases, however, like the Willow, Poplar, Elm, in which the seed ripens early, sowing may take place during the summer months. The seed land is prepared by ploughing or digging, and harrowing and raking, until it is brought to a fine tilth. Drills are then drawn at regular distances apart, varying from 3 in. to 12 in. according to the kind of seed that is sown, each kind being covered with three or four times its own depth of soil, and afterwards lightly rolled. In some cases seeds are sown broadcast over beds about 5 ft. wide, but generally speaking it is more economical, and better for the seedlings, to sow thinly in drills. To allow for cultural attention like weeding, hoeing, watering, etc, the seedbeds should not be more than 4 to 5 ft. wide, with an alley between, so that half the seed-bed may be attended to from one side and half from the other without having to tread upon the soil between the plants.
The forest and other trees raised in large quantities from seed are Oaks, Beeches, Birches, Ashes, Poplars, Sweet Chestnuts, Horse Chestnuts, Elms, Hollies, Hawthorns, Hornbeams, Limes, Mountain Ashes, Planes, Sycamores, False Acacias (Robinia), Maidenhair Trees (Gingko), Willows, Tulip Trees (Liriodendron), and such conifers as the Firs, Spruces, Pines, the Arbor Vitae, Cedars, Thuyas, Larches, Cypresses, etc.
Apart from the forest trees, there are hundreds of others of a more ornamental character, chiefly used for the decoration of large parks and gardens, public places and squares, streets, etc. These are raised not only from seeds in the same way as forest trees, but in the case of special varieties, or when seeds are not ripened in abundance, they are also raised by means of cuttings, layers, buds, grafts, and suckers. The most important plants in this group and in the forest section are dealt with in Vol. II in the article on "Trees and Shrubs", to which the reader is referred.
Of late years a great trade has sprung up, chiefly amongst nurserymen, in ornamental flowering shrubs, which are grown in pots and gently forced into early bloom in Spring (January to March and April). The principal plants thus grown are Lilacs, Double Cherries, Azaleas, Almonds, Japanese Quinces, Wistaria, Double Plums, Cydonia Maulei, Pyrus spectabilis, Deutzia gracilis, Staphyllea colchica, Prunus triloba, Magnolia Soulan-geana, Forsythia suspensa, Ribes sanguineum, etc. etc.
A trade also has sprung up again in clipped trees and shrubs of an evergreen character. Such trees as the Box and the Yew, the Poet's Laurel, and others are cut into various shapes, some more or less fantastic - as shown in the photograph (fig. 1). They are usually grown in tubs, and are utilized for what some people call decoration, but others desecration, of large gardens. [J. W.]
Fig. 1. - Clipped Trees and Shrubs.
Photo. Chas. L. Clarke.