HEDGES AND HEDGE – PLANTING.

New Zealand Journal of Agriculture, Volume XV, Issue 2, 20 August 1917, Page 69

HEDGES AND HEDGE - PLANTING.

W. H. Taylor,

Horticulturist.

The fact that there are so many species of trees and shrubs that can be, and are, used to form hedges is often a source of embarrassment to intending planters. In some parts of New Zealand almost any species will succeed, but in others the choice is more limited. Among species that are seriously affected by local conditions may be mentioned the golden akeake (Olearia Forsteri). This native shrub makes a most excellent hedge in the cooler parts and where the soil is deep and rainfall fairly abundant, but it is a complete failure if subject to dry conditions of soil, particularly if associated with a warm climate. The growth becomes stunted, and a gall insect attacks the young shoots. In similar conditions holly and euonymus, both splendid hedge - plants in favourable situations, are nearly killed by scale insects, the damage being great because growth is poor. Laurestinus in dry conditions becomes a prey to thrips, and Chatham Islands akeake (Olearia Traver si} to the borer. Individual taste is, of course, a factor to be reckoned with : some do not care for the yellow foliage of the golden akeake, preferring the darker green of the laurestinus, escallonia, and similar dark-foliaged plants. The purpose for which a hedge is required should also be considered. In some cases it is a wind-screen that is needed, which may be better provided by planting trees of moderate growth, such as the black wattle or Pinus muricata, or a compact tree such as the Lombardy poplar. These make lines rather than hedges.

TALL HEDGES.

The cost of trimming hedges has always to be reckoned with, and the taller the hedge grows the more expensive it becomes. The work of trimming hedges from a platform is bound to be slow. It is therefore advisable when proposing to plant for a tall hedge to select a species that will cost as little as possible for its ■ maintenance. No tree can make a good hedge unless it keeps its lower branches. With few exceptions the' pines become bare at the bottom after some years, and the same is true of the black wattle. . Cupressus macro carp a should, in my opinion, be barred. It is liable to die out at any time, ; more particularly if it is cut much; if it is not cut it occupies too much space 1 ; and trimming a macrocarpa hedge of any height is expensive. There are three trees well adapted to form high hedges that cost comparatively little to -trim. Cupressus torulosa elegdns

(sometimes the ■ middle . word is omitted).' planted about 4 ft. apart requires no trimming, except maybe a little on the lower branches. The tree will thrive almost'anywhere, and appears not to be particular as to soil. The drawback is that, for some reason the trees are expensiveprobably because there has been little demand for them. Cupressus Lawsoniana is probably the hardiest tree we have, and, planted 4 ft. apart, it makes a magnificent tall hedge. Trimming should be done by pruning rather than shearing— is, cutting out branches to limit its width and leaving the rest alone. The third tree, Acmena floribunda, is of a different type, and may be described as a giant myrtle. It should be planted 6 ft. apart to make a tall hedge; trimming is inexpensive, as it is easy to cut. The acmena has long been known in New Zealand as a well-doing handsome tree, but it is only quite recently that nurserymen have offered it in quantity for hedges. .

GARDEN HEDGES.

Hedges in a garden are usually required to be kept within comparatively narrow limits. They may be required for subdivision in the garden, as a boundary-hedge outside shelter-trees, or in the case of quite small places the hedge may be the only screen from outside view. The first things to consider are the local condition of the soil and the normal rainfall and climate. In the South Island and the south end of the North Island there is a large choice of varieties. For the more northern districts the choice is more limited, because, as previously indicated, a number of species that make good hedges will not thrive in the warmer climate, where they become a prey to various insect pests.

Three species may be mentioned which do uniformly well in any part of New Zealand namely, Eleagnus japonica, Cupressus Lawsoniana, and the privets, of which the common privet {Ligustrum vulgare) makes the neatest hedge. These are specially mentioned because they make perfect hedges. The Lawsoniana can be kept to narrow limits, and does as well as when allowed to grow to a larger size.

In addition to these three species the following are also serviceable in northern districts: Pittospdrum tenuifolium, P. Colensoi, P. eugenioides, P. crassifolium, P. undulatum, Escallonia pterocladon, Buddlea globosa, Osage orange, T ecoma capensis, Ligustrum sinense, Berber is vulgaris.

For other parts of the Dominion all the foregoing list may be used except Tecoma capensis and Osage orange, which would not succeed in the coldest places. In addition the following are suitable : Berberis Darwinii, Coprosma Baueriana, Escallonia macrantha, Euonymus japonica, holly, yew, laurestinus (giant), Olearia Forsteri, Olearia macrodonta, laurel (common), Rhamnus alaternus (buckthorn).

Buckthorn I consider the best of all for a hedge of moderate size, but none of the nurserymen appear to stock.it, which is a great pity. The plants are easily raised from seed, and the seed is freely produced. Some years ago I planted a hedge of it, and young plants sprang up in large numbers alongside the hedge. All the plants mentioned are capable of forming good hedges, provided they have suitable conditions. Those specified in the last list require fairly good soil and a fair rainfall; most of them would fail under very dry conditions.

Eleagnus requires to be planted in a double line, as a hedge of it planted in a single row will blow over. For this reason, and as it cannot be kept very narrow, it is not suitable for planting in small places. The common privet is the best of all plants for making a low and narrow hedge; this opinion is strengthened by personal observations in many parts of the Dominion. It is said that privet is very exhausting to the soil, and it certainly has that drawback, being a surface rooter ; but the exhaustion to the soil is naturally comparative to the size of the hedge, and if growth is restricted to narrow limits the value of the hedge compensates for any loss in the soil.

Preparing the Site.— No hedge can really thrive unless the roots have a good run. A narrow trench dug in hard soil does not provide this condition, yet frequently nothing more is possible. In such cases the surface should always be kept clean and well worked, and if surface digging can be extended some distance it will assist the plants, particularly by enabling rain to enter more freely. When trenching be sure to keep the original surface soil on top. In gardens the whole area should be trenched.

Planting.— Eleagnus, Tecoma capensis, and Osage orange should be planted in double lines, 9 in. or 10 in. apart, and 2 ft. 6 in. apart in each row. All other species may be planted in single line, common privet 10 in. apart, and other plants from 12 in. to 15 in. As to the time for planting, my own experience is that, on the whole, spring-time is the best season, giving better results than autumn planting.

Trimming. A common mistake is to cut the tops irrespective of the habit of the plant. This makes the hedge slower in reaching a given height; there is no compensating advantage in many cases, and it causes the hedge to broaden more than is desired. Olearia Forsteri, holly, and the various pittosporums do not require topping until several years after planting. Eleagnus has a habit of making a number of long thin growths. Those that come out at right angles from the line of the hedge should be cut back, but those on the top should be knotted together ; if the ends of two shoots are brought together from opposite directions it will be found they can be wound round each other so as to form a knot, and they will retain that position. The effect will be to greatly strengthen the hedge and hasten

its upward progress. Trimming should not be too severe during the first year of a hedge, as .growth makes corresponding roots. 'ln afteryears trimming can be done at any time the state of growth requires it the time of cutting does not affect the tree.

FARM HEDGES, ETC.

In the foregoing matter the subject has been treated mainly from the horticultural, or homestead aspect. Where hedges of considerable extent are required, and it is desired that they should keep in live-stock or be proof against intruders, I consider that barberry {Berber vulgaris) or the cherry-plum (JPrunus myrobalana) are the best plants to use. Eleagnus would have the desired effect,- but -the cost of. trimming it is considerable. The cherry- can be raised from cuttings. The plants , should be set in double rows 9 in. or 10 in. apart, and the plants 30 in. apart in each row. In the winter following planting the plants should be all cut - down to within 6 in. of the ground ; or if growth has not been good delay the cutting-down for a year. As a result of the cutting-down the plants will each throw up a number of very strong shoots, which make the foundation of a hedge proof against cattle. Barberry should be planted in the same way —namely, in double rows, and at the same distances. On good soil barberry will make an impenetrable hedge, though not so strong as the cherry-plum.

African boxthorn (Lycium horridum) makes a most excellent hedge that appears to be very hardy and capable of withstanding salt-laden gales from the sea. It has, however, the disadvantage that its very strong and sharp thorns are poisonous, and it thus contains a considerable element of danger to man and beast on the farm. In a number of cases boxthorn hedges have been cut out on this account. If, however, it is thought worth while to face these drawbacks, and also the further danger of the plant being spread by birds carrying the seed, it can be depended on to make a formidable hedge. Hawthorn under New Zealand conditions has too many disadvantages for it to be recommended as a hedge-plant.

Tagasaste (Cytisus proliferus) is frequently used with good effect to provide quick shelter, a role it fills very well. It was not included in the foregoing list of hedge-plants, as it does not form an ideal hedge.

It is reported that an arrangement has been made between the Governments of the United States and Canada whereby all farm labour necessary for the harvest would be collected in Kansas in July and gradually moved northwards and distributed by the two Governments in co-operation, thus making good the deficiency •'in men in Canada resulting from the war. ' . '