Hedges are much less used in this country than in Europe, and for several reasons. Our climate is dry, and most hedges do not thrive so well here as there; labor is high-priced, and the trimming is therefore likely to be neglected; our farms are so large that much fencing is required; timber and wire are cheaper than live hedges.
However, hedges are used with good effect about the home grounds. In order to secure a good ornamental hedge, it is necessary to have a thoroughly well-prepared deep soil, to set the plants close, and to shear them at least twice every year. For evergreen hedges the most serviceable plant in general is the arbor vitae. The plants may be set at distances of 1 to 2-1/2 feet apart. For coarser hedges, the Norway spruce is used; and for still coarser ones, the Scotch and Austrian pines. In California the staple conifer hedge is made of Monterey cypress. For choice evergreen hedges about the grounds, particularly outside the northern states, some of the retinosporas are very useful. One of the most satisfactory of all coniferous plants for hedges is the common hemlock, which stands shearing well and makes a very soft and pleasing mass. The plants may be set from 2 to 4 feet apart.
Other plants that hold their leaves and are good for hedges are the common box and the privets. Box hedges are the best for very low borders about walks and flower-beds. The dwarf variety can be kept down to a height of 6 inches to a foot for any number of years. The larger-growing varieties make excellent hedges 3, 4, and 5 feet high. The ordinary privet or prim holds its leaves well into winter in the North. The so-called Californian privet holds its leaves rather longer and stands better along the seashore. The mahonia makes a low, loose hedge or edging in locations where it will thrive. Pyracantha is also to be recommended where hardy. In the southern states, nothing is better than _Citrus trifoliata._ This is hardy even farther north than Washington in very favored localities. In the South, _Prunus Caroliniana_ is also used for hedges. Saltbush hedges are frequent in California.
For hedges of deciduous plants, the most common species are the buckthorn, Japan quince, the European hawthorn and other thorns, tamarix, osage orange, honey locust, and various kinds of roses. Osage orange has been the most used for farm hedges. For home grounds, _Berberis Thunbergii_ makes an excellent free hedge; also _Spira Thunbergii_ and other spireas. The common _Rosa rugosa_ makes an attractive free hedge.
Hedges should be trimmed the year after they are set, although they should not be sheared very closely until they reach the desired or permanent height. Thereafter they should be cut into the desired form in spring or fall, or both. If the plants are allowed to grow for a year or two without trimming, they lose their lower leaves and become open and straggly. Osage orange and some other plants are plashed; that is, the plants are set at an angle rather than perpendicularly, and they are wired together obliquely in such a way that they make an impenetrable barrier just above the surface of the ground.
For closely clipped or sheared hedges, the best plants are arbor vitae, retinospora, hemlock, Norway spruce, privet, buckthorn, box, osage orange, pyracantha, _Citrus trifoliata._ The pyracantha _(Pyracantha coccinea_) is an evergreen shrub allied to cratgus, of which it is sometimes considered to be a species. It is also sometimes referred to cotoneaster. Although hardy in protected places in the North, it is essentially a bush of the middle and southern latitudes, and of California. It has persistent foliage and red berries. Var. _Lalandi_ has orange-red berries.