The buckthorn has the advantage of great hardiness, thick growth, and easy propagating and transplanting, and requires but a moderate amount of cutting back. But the growth is not stout enough to resist unruly animals, unless in very rich soils, and even a moderate amount of cutting back is an objection to farmers.
The cost of buckthorn hedges, including the preparation of a strip of soil five feet wide, purchase of plants, setting, and occasional horse cultivation on each side, was about twenty-five cents a rod the first year. The yearly cultivation and cutting back, until the hedge had reached full size, was three or four cents a rod. Though the buckthorn has nearly passed out of use on account of its inefficiency, it is not impossible that it may be extensively planted when cultivators find that it may be converted into an efficient barrier by inclosing two or three barbed wires extending its length through the interior—these wires, supported on occasional posts, being successively placed in position as the hedge increases in height, the branches growing around the wires and holding them immovably in position. Galvanized wire should be always used, on account of its durability.
Osage orange hedges require more care than buckthorn, in assorting plants of equal size and vigor, and the rejection of feeble plants. Like all other hedge plants, they should be set in a single line, and eight inches apart is a suitable distance. For the first few years the ground must be kept well cultivated. It is partly tender and will not endure the winters at the North, unless on a well-drained soil. Hence the importance of placing a good tile drain parallel to the hedge and within a few feet of it. Thus protected, good hedges have stood for twenty-five years where the thermometer has often shown ten or twelve degrees below zero, and sometimes lower.
No hedge is more commonly mismanaged than the Osage orange. It is planted in imperfectly prepared ground; vigorous and feeble plants are planted indiscriminately, cultivation and pruning are omitted or not done thoroughly, resulting in broken and irregular lines. When more care is given, the hedge is nearly spoiled by being pruned too wide at the top, the heavy shade above causing meagre growth and openings below. It should be pruned in wedge shape, but shearing is objectionable as causing a thick and short growth of leaves at the exterior, excluding light from the inside and causing bare branches there. Cutting back more irregularly with a knife allows the growth of interior foliage, and gives more breadth to the hedge. The sheared hedge presents an unnatural stiffness in ornamental grounds; but skillfully cut back with the knife it has more of the beauty of natural form. The manner of pruning is very important, both as regards utility and beauty. For farm barriers hedges do not require so elaborate care. Another mode of treatment has been adopted in the Western States. The trees are trimmed and the main stems trained upright for a few years. They are then cut half off at the ground and bent over at an angle of thirty degrees with the ground, a tree being left upright at distances of four or five feet, and the inclined ones interwoven among them, a straight line of trees being thus formed. The tops are then cut off about three feet high. New shoots spring up in abundance and form an impenetrable growth, as many as fifty having been counted from a single plant the first year. The top is cut to within a few inches each year of its previous height. Hedges made in this way have no gaps.
A similar treatment may be adopted when a hedge becomes too high by long years of growth. The trees are first partly trimmed with a light axe or hook with a long handle, and then half cut off at the ground and bent over. A new growth will spring up and form a new hedge. This course was adopted by the essayist with a hedge planted twenty-eight years ago, and which has been a perfect farm barrier for more than twenty years. The cost of this hedge was about twenty-five cents a rod the first year, and the three subsequent cuttings for sixty rods cost about twenty dollars, averaging less than a dollar a year. But it was usually too tall and shaded, and occupied too much ground, to be recommended where land is valuable.
Ninety rods of Osage orange hedge, properly trimmed, cost about the same for the first four years of cultivation, but more for annual cutting back. It was planted twenty-four years ago, and has been a perfect barrier for about twenty years. The yearly cost of pruning was about four cents a rod for ten or twelve years, and since it has become larger and higher nearly double. For cutting back a stout hook with a handle two and a-half feet long or a stout scythe was used. Hedge shears are too slow except for ornamental hedges, and even for these the knife is preferable.
The Honey locust has been extensively used for hedges of late years on account of its hardiness. Seed should be selected from the most thorny trees. The trees have a tall, slender, and not hedgy growth, and require thorough cutting back to secure a thick mass of branches at the bottom, and very few have received this treatment when young. The care in planting and rearing is similar to that required by the Osage orange.
Many hedges have been injured or even destroyed by pruning after the summer growth has commenced. The pruning must be done in spring before the buds swell, if vigorous growth is to be preserved. But strong-growing hedges, that are likely to become too high, may be checked by summer pruning.
Though the cost of planting and starting a hedge is less than that of building a good board fence, they are not adapted to farmers who will not give them the continued care required to keep them in good order. This conclusion is justified by observing how few have succeeded with hedges, and many have allowed them to be ruined by neglect.
The evergreens which have been employed have been exclusively for ornamental screens, and not for farm barriers. The Norway spruce may be placed at the head on account of its rigid growth, hardiness, and the freedom with which it may be cut back, it will bear more shade than many other evergreens, and hence the interior of the screen is green with foliage. The cutting back should be done with a knife, and not with shears. Next to the Norway spruce is the hemlock, which excels the former in its livelier green in winter, while it is unsurpassed for retaining interior foliage. It will bear cutting back to an almost unlimited extent in spring before growth commences. But it is not so stiff as the Norway spruce as a barrier. The American arbor-vitæ, though much used, becomes destitute of foliage inside, and is browned by winter.