FARM HEDGES.

New Zealand Journal of Agriculture, Volume XXIII, Issue 5, 21 November 1921, Page 284

FARM HEDGES.

W. H. TAYLOR,

Horticulturist.

The importance of good shelter-hedges is so well understood that it requires no recapitulation. The subject of hedges themselves is worthy of consideration, however, not only for the benefit of farms in the making and those yet to come, but also because the outbreak of the fireblight disease may render it necessary to replace many hedges already established. The hawthorn has been very extensively planted, particularly in the North, and, whatever may be the fate of the existing hedges, no more will be planted, this being now prohibited under the Noxious Weeds Act.

The question then arises, What kind of hedge is likely to be adopted ? Observation and a considerable volume of correspondence dealt with by the writer show that, a hedge that requires much trimming will not find general favour. The hawthorn hedges referred to are in most cases untrimmed, the trees being left to grow their own way. This means that they are not hedges in the proper sense, but rather should be termed wind-breaks, and it appears fhat the question should be approached with this consideration in mind. It is extremely improbable that much labour will be expended in the maintenance of hedges, and, except in the case of comparatively short lengths such as for subdividing home paddocks, it would be futile to use plants that demand regular trimming. In this article shelter-belts will not be dealt with any further than to say that in many cases a narrow belt would be . a better investment than a single line of trees so-called hedge. There are, presumably, two chief reasons for planting a single linenamely, economy in cost of establishment and in space of land occupied. The hawthorn met these requirements very well. It is here proposed to deal with such plants as come nearest to the hawthorn in these respects,, and also to refer to those that make good hedges in the proper sense. It may be premised that a certain amount of trimming is needed in every case.

SOME HEDGES AND THEIR ESTABLISHMENT.

_ Chinese Privet (Ligustrum sinense). — The Chinese privet is an evergreen, a very strong and rapid grower, and makes a small tree 18 ft. to 20 ft. high. It is as much at home in localities of dry climate and poor land as in a moist climate and rich soil. Subject to no disease or special insect pest, this plant should do well everywhere. A cattle-proof fence can be made by planting in double row in .quincunx order, plants in each row 30 in. apart and rows 12 in. apart. Side trimming should be practised for the first few years so as to thicken growth. The tops may be merely tipped or not touched at all, this to be judged by length of growth. If it is left untrimmed, later on the plant would in general form of growth approach more nearly to the hawthorn than any other plant I know suitable for the purpose, unless it be the cherry-plum. A great advantage with this privet' is that new growths appear wherever a branch has been cut

back, and it can be cut . back to any extent. The whole hedge might be cut to near the ground, and it would again make good growth. A certain amount of trimming or shortening - back of branches is at times necessary to maintain a close breakwind. The plant is raised by cuttings, and transplanted without trouble or risk of losses. Lawson’s Cypress (Chamaecyparis (Cupressus) Lawsoniana). — For making an evergreen hedge or breakwind this cypress is probably not excelled except by one other tree, the yew (Taxus baccatd), which need not be considered, as it is too slow in growth for the purpose, and is poisonous to cattle. The Lawsoniana, as it is commonly called, will make an excellent hedge of small dimensions,, a large hedge, or merely a breakwind, which'means that it will bear the cutting necessary to restrict spread, and also close planting. Cutting-back must not be to bare limbs ; they will not break. There must .be always growth behind the cut, which implies the necessity for frequent attention if restricted spread is desired. It stands wind better than do gum-trees, and is not particular as to soil, provided there is a fair depth to root in. Restriction of growth is necessary, for if left to grow naturally the trees would occupy too much space. Clipping by shears is not good practice, nor is trimming with a slasher.' Pruning by knife or seccateurs is the proper method ; a billhook can be used for topping. It is raised from seeds, and is rather slow growing as a seedling. The young trees are never likely to be very low in price. Plant 3 ft. apart.

Cherry-plum (Prunus cerasipera). — This is the well-known cherryplum or myrobalan. In it we have a tree that will make a cattle-proof fence in a short time and with small cost in attention. Cuttings strike quite freely. They should be raised in a nurse-bed, and planted in the autumn or spring following. Plant 18 in. apart. The young plants should not be severely pruned ; merely cut back straggling shoots and reduce the tops so as to make a shapely plant. During the first season allow the plants to grow without any trimming ; the more growth they make the better. Towards the end of the next winter, before new growth begins, the plants should be cut, down to within 6 in. of the ground, which is easily done with a slasher. A number of strong shoots will be made as a result of cutting back, which will give the hedge a very strong base. I have known this to result in a sheep-proof hedge by the end .of the season. Growths are strong, and furnished with strong spines. ' There need be no hesitation to apply this treatment. A cut-back hedge will at the end of a year be much larger than a - hedge not so treated. It may be asked, Why not cut the plants down when they are'planted ? That would not do at all; the result would be weak growth. It is necessary to establish a good root-system before cutting down. This is the method by which the fine hawthorn hedges seen in the Old Country are established, except that they are allowed to grow for two years before being cut down. Any future trimming (and a first-class hedge or breakwind requires it) can be easily done with a slasher. The cherry-plum shows the same adaptability to soil and climate as does the Chinese privet. Boxthorn (Lycium horridum). — There is no question about boxthorn making a good hedge ; it can be made quite cattle-proof by the same cutting-down as detailed for the cherry-plum. There are, however,

some disadvantages connected with boxthorn that should be mentioned. It is an exceedingly spiny plant, and the spines cause poisoned wounds that are difficult to heal. When trimming it the hands of a workman must be protected by good leather gloves. All trimmings must be cleared up, for the spines injure the hoofs and fetlocks of animals. In addition to this, trimming is rather difficult work unless done frequently. The wood is hard, and it is an awkward hedge for a slasher. If after the hedge has been well established it is allowed to run it will make a good breakwind about 15 ft. high. An untrimmed hedge, however, will fruit freely, and if the plants spread to waste or hilly land, it becomes a very serious pest. The usefulness of the boxthorn hedge to the Taranaki dairy-farmer has to be seen to be properly appreciated. Boxthom is extensively planted in many parts of Australia, particularly Victoria and South Australia, • where it makes a magnificent hedge. The main argument against this plant in Australia arises from its spreading habit, in consequence of which the plant, over some areas, has been declared a noxious weed other than when in the form of a well-trimmed hedge. Very strenuous efforts are being made to get the law altered so as to secure the complete eradication of the plant, and it appears likely that this will eventuate. In these circumstances it appears to me that while the boxthorn makes an excellent hedge, even in poor soil where many plants would not succeed, and is well adapted for use as a hedge where it can be kept trimmed, it would be unwise to plant it where the extent of hedges would preclude proper trimming. If used, plant 18 in. apart. It is raised from seeds; plants are low in price. The resisting property of boxthorn to strong, salty winds off the sea is a point in its favour which should be noted.

Lombardy Poplar (Populus fastigiata). The upright poplar is largely used for shelter purposes, particularly in Hawke's Bay. Here may be seen trees of giant size, and in other cases, where planted closely (sometimes 2 ft. apart), tall and narrow wind-breaks. This tree can be easily raised from cuttings, which may be small or large. In good and fairly moist soil cuttings 6 ft. to 8 ft. long may be used. Make the holes with a crowbar, let the foot of the cutting rest on the bottom of the hole, and tamp the soil firm around it. After a line of cuttings has been put in the tops should be cut off to one level. It is bad practice to drive cuttings in with a mallet, as is often done ; the bark at the foot is torn off, and the cutting roots feebly from higher up. Where, very dry summers are experienced cuttings are not reliable, and rooted trees should be planted. One of .the best breakwinds I have seen is a double row of poplars, the rows 4 ft. and trees 2 ft. 6 in. apart, with ■ Elaeagnus japonica planted in the middle. The Elaeagnus climbed the poplars and required no clipping. An advantage of poplars is that the wood being very soft it costs little to top them now and again when they exceed the desired height. There is an idea prevalent that the poplar suckers badly, but that does not apply to the Lombardy poplar. Macrocarpa Cypress ( Cupressus macrocarpa) . — appears to be necessary to mention this tree, though personally I have always been opposed to its use as a hedge. Because young trees are comparatively cheap and it is a fast grower it has been extensively planted in hedges.

The two qualifications mentioned are all that is in its favour ; everything else is against it. It is expensive to clip, as this must be done with shears, and clipping must be frequent or the hedge will cover too much space. It dies out under constant clipping, although dying may be deferred for a good many years. It is practically impossible to fill gaps where trees die. The expense of maintenance should condemn it even if it were permanent. If left unclipped it not only covers an inordinate amount of space, but eventually becomes bare at the bottom, when a draught is created that is worse than no shelter at all. In brief, the macrocarpa cypress is a very valuable tree in its proper place —which is not as a hedge.

Osage Orange (Madura aurantiaca). — This makes an excellent hedge up to about 15 ft. in height. It bears cutting to any extent hedges reduced in height and cut back to the bare trunks break again quite freely. It is suitable for the warmer districts only. Raising is done from pips. • *

Common Barberry (Berberis vulgaris).— This is a great favourite with farmers; it makes a cattle-proof hedge with little attention. Plant in double row in quincunx order, 30 in. apart in each row, rows 12 in. apart. Easily raised from seed, it is one of the cheapest plants. It is necessary to mention that in some districtsTaranaki in particular —the barberry is spreading to hilly land by birds carrying the seeds. On this account barberry is now included in the Third Schedule of the Noxious Weeds —-that is, the local body may declare the plant a noxious weed. In Taranaki it is now allowed only, where regularly clipped to restrict fruit-bearing, and it is liable to be declared in other districts.

yElaeagnus japonica. —-No plant makes a stronger hedge than this, though it is not a lofty one. It must be planted in a double row as detailed for the barberry. A single row will not stand, as the plant does not make a strong trunk. Its disadvantage is that the trimming is expensive. This cannot be done with a slasher, and the operation must be frequent. The hedge should be clipped twice a year; one clipping would be more expensive than would two. This bars its use except for comparatively short lengths of hedge, but for that purpose it is excellent. It would be useless to plant Elaeagnus unless with the intention of clipping, for naturally it is of a sprawling, semi-scandent habit, and it would not stand up. It is not easy to think of any other plant that would be generally adaptable as a short farm hedge in various parts of the Dominion, and certainly none equal to .those already mentioned.

Other Hedges.— Some of the Pittosporum species make nice hedges, but not cattle-proof. Olearia -F or st er i makes a splendid hedge in some places, and fails in many others. This plant is subject, to attack by a gall-insect, Cecidomya olearia, closely related to the Hessian fly. When growing in poor soil or in a dry climate or situation the attacks of this gall-insect stunt growth to such an extent that the hedge is made useless. In a climate that suits it holly makes a very fine hedge, but in the warmer districts it is worthless. It becomes a prey for Lecanium scales that cover the leaves with honeydew, which in turn becomes covered with a black fungus, choking the pores and starving the plant.

Preparing the Site and Planting.

The ground should be broken up some time before planting the hedge, so as to allow time for the soil to sweeten, and all clods should be well broken up. A fair depth of rooting-medium is necessary and should be provided. Where the subsoil is naturally loose it will be sufficient to break up the surface soil, but where the subsoil is clayey or hard a narrow strip deeply worked may become merely a trench filled with water. This can be prevented by throwing up soil from the side, which will raise the surface and obviate the necessity for deep working, and at the same time form a water-table to carry surplus water. When planting, strike the spade down perpendicularly where the first plant is to stand, throwing the soil forward. Place the roots against the perpendicular wall thus formed, dig soil up to it, and tread firm. Then dig towards the plant to a little beyond the site- for the next plant. Strike the spade’down again, dragging the soil back to leave another perpendicular wall, and so on throughout the planting. This is the quick and safe method. Any attempt to spread roots will not only delay the work of planting, but will also tend to increase the proportion of losses. It is necessary to protect a young hedge from sheep and cattle by double fencing or otherwise. I have not seen the plant that sheep will not eat, and cattle will often eat a plant when it is young that they will not touch when well grown. In any case, cattle would trample young plants down and tramp the soil hard, and this ■ should be kept loose and free of weeds for at least two years.