Hedges in the flower Garden

New Zealand Journal of Agriculture, Volume 94, Issue 6, 15 June 1957, Page 611

Hedges in the flower Garden

LJ EDGES serve many useful purposes, ornamental as well as practical, and consequently ■ ■ are dominant features of many home gardens. Because their prominence attracts attention, their condition is of major importance where they are used extensively. Wellkept hedges of carefully chosen species can blend into the garden plan, whereas the discordant effects created by unsuitable or ill-kept hedges cannot be masked even in the best of gardens. This article by J. S. Say, Horticulturist, Department of Agriculture, Auckland, deals with the selection, planting, and maintenance of hedges in the home garden. The notes on work in the flower garden in July are by Rosalie A. Campion, Horticultural Instructor, Department of Agriculture, Wellington.

MOST people think of hedges as a means of giving protection of some kind, from wind or wandering animals, or the gaze of passersby or neighbours. This severely practical approach with little imagination in the selection of suitable plants has resulted in common, hardy plants such as privet and Chdmaecyparis lawsoniana being so widely planted as to become monotonous. Though protection is the primary function of hedges, they may be given far more importance in garden design.

There is no reason why beauty should be sacrificed to utility. Hedges can be used as backgrounds to flower or shrub borders or as divisions between different sections of the garden; for example, between the vegetable and the flower gardens. With suitable plants they can be used as ornamental features in their own right by providing colour , with leaves, flowers, and berries. ' Types of Hedges Hedges may be grouped into two main types, formal and informal.

Formal, trimmed hedges are by far the most common. They are a legacy from the old custom of surrounding homes and gardens with tall, dense hedges to give complete privacy even at the cost of cutting out sunlight and views. For some sections or parts of sections formal, trimmed hedges are still the most suitable as screens or as protection against wind. In many circumstances they give the greatest measure of protection while taking up the least amount of space, but it is seldom

either necessary or desirable to grow the all too common massive, dark hedges of earlier days. Formal hedges of low to medium height are ideal for defining boundaries or as dividing lines within gardens without giving a completely enclosed appearance. They make excellent backgrounds for formal gardens and

are comparatively easily maintained in good condition. Tall formal hedges also have their uses principally as windbreaks. Their greatest disadvantage lies in the amount of maintenance work required. The need for regular and careful trimming is greater if the undesirable features of width and heaviness are to be avoided.

As with other trees and shrubs the choice of suitable hedge plants may be restricted by soil and climate, but the most attractive species in the available range should be chosen. Informal hedges may be rows of shrubs or small trees whose natural growth habit and height are such that they may be left untrimmed. A row can consist of one or more species. The screening and protective functions of hedges may also be provided in an attractive form by the shrub borders. The latter practice gives the greatest scope for effective planting and can be used in most large gardens and is by no means impossible in small sections. Less formal protection demands more careful planning, but there is much more scope for imaginative planting, the result is more pleasing, and neither protection nor privacy need be sacrificed. Formal and informal plantings may be used in different parts of the same garden and, with thoughtful planning of the whole, can be made to blend one into the other. Selection The selection of suitable plants for a hedge usually receives far less thought than is given to the choice of any other plants. Apart from the choice of salt-resistant plants for the seaside, it is only on rare occasions that the gardener considers the many

other points necessary for the establishment of a good hedge. mu „ , . , . uz, whethe? ahedge is Really necessary whether a hedge is really necessary. Very frequently hedges are put m just as a matter of course. They serve no useful purpose and could well be done without. For example, hedges round the front boundaries of town sections are often unnecessary, for very few people wish to be completely screened from the street, and hedges less than 6ft. high are not effective screens. Anything less than this can be overlooked and the purpose of the hedge is defeated. In such cases dwarf hedges or groups of shrubs are sufficient to define the boundaries, and the appearance of the street as a whole is improved by the absence of large often unsightly hedges of various heights, shapes, and conditions. On sloping sections it is difficult to screen off the house from the road and in such positions, too, hedges are often of little use as windbreaks unless they are very tall. If a hedge is necessary or desired, its exact purpose should be decided; that is, whether it is to be a windbreak, ’ a screen, a background, a

boundary, or an ornamental feature, It may combine any two or more of these functions. Once the purpose of the hedge is defined the type and other characteristics can be considered. The nex f point to decide is whether ft should be formal or informal. Only about a dozen species of plants are commonly used for trimmed hedges in New Zealand, but many other plants would be suitable. Formal hedges require plants with small, dense foliage and o f compact growth. They must be able to stand frequent clipping and produce abundant short growths even if slow i y , an d be resistant to ’talerant ot attacks by pests and diseases. Nearly all conifers though fulfilling most of these conditions, are unsuit- , n . „ , bpca ..„ p thev able for small gardens because they are liable to die out it trimmed too hard. Plants with large leaves are usually unsuitable for formal hedges because they do not quickly reclothe with foliage after being trimmed, but coloured and variegated leaves can be used in selected positions. A hedge of golden euonymus, for example, can be used as a feature in the garden, but

would be unsuitable as a background to a rose garden. f Many shrubs can be used for informal hedges. In fact almost any shrub with a reasonably compact habit of growth and dense foliage can be used. Shrubs with coloured or variegated foliage, flowers, berries, or autumn colour are the most suitable, Evergreens are preferred for singlerow hedges, but deciduous shrubs can be included in shrub borders. The selected variety must be able to rea ch the required height, but it is most important to choose one which can be easily maintained at that level, Even with frequent clipping many hedges tend to grow too large and eventually have to be cut back severely, often with disastrous results, With informal hedges the required height should be maintained with the minimum of pruning When hedge plants are being bought it is always advisable to ensure that they are suitable for the soil and climate. Most of the commonly grown ones are fairly tolerant of a wide range of soil types, but will not stand poorly

drained positions. On sandy, dry, or continuously moist soils extra care must be taken in the selection. Tender plants should not be planted in cold climates and salt-resistant varieties are necessary near the sea.

Planting

Probably no other group of plants receives such scant attention as hedges at planting time. As a rule the first thought of owners of new sections is to plant hedges, and plants are put in with little or no soil preparation. Too often the result is that many die and the remainder struggle on but never make satisfactory hedges. It .is far better to miss a season so that the position can be prepared, for in the end a satisfactory hedge will be established in a shorter time. A hedge is a permanent feature of the garden and deserves the best treatment. Drainage is essential and should be attended to first, but tile drains should not be laid beneath or near hedges, because roots soon block the tiles.

At least 2 months before the usual planting season a 2ft. wide strip should be dug as deep as the topsoil allows and the subsoil loosened. A good dressing of a balanced fertiliser should be worked in and some organic matter

if it is available. Planting times and methods discussed in articles on trees and shrubs in the April and May issues of the “Journal” apply equally to hedges. Distance. apart depends on the growth habit, size, and purpose of the hedge; 12in. to 18in. is usual for dwarf and medium-sized species and 2ft. to 3ft. for taller ones. Generally it is better to overplant than underplant, for the plants grow together more quickly and a close-knit hedge is established in a shorter time. Recommendations for shrub borders, which may be used instead of more formal hedges, were given in last month’s issue of the “Journal”. Care after Planting Watering and weeding should not be be neglected, especially during the first 2 or 3 years. To encourage good, vigorous growth a slow-acting, balanced fertiliser should be applied each spring until the hedge is well established. Only on poor soils are regular applications of fertilisers necessary for established hedges. Mulches of organic matter are also helpful in the early years. Training and Trimming Unless the plants, when received from the nursery, are compact and bushy with good root systems, they should be cut back fairly severely at

planting time to encourage a mass of young shoots low down. During the first summer they should be treated as individuals and the tips of the shoots pinched out at an early stage. If this is not done, they should be pruned fairly hard in winter or spring 12 months after they are planted. Individual treatment may be necessary for a further year, but after that the hedge can be treated as a whole and trimmed with shears. The foregoing recommendations do not apply to conifers, as the majority will not stand hard cutting. With them it is most important to trim the sides from an early stage to encourage a bushy habit and to prevent the hedge from becoming too wide at the base and then having to be cut back hard into old wood which does not readily refurnish with new growth. This is one reason why many hedges of Chamaecyparis lawsoniana are bare at the base. Early pruning is best done with secateurs. Well before the required height is reached conifers should be tipped and the resultant side shoots regularly pinched to encourage a wellfurnished top which will grow up in an even line. If they are not tipped until the required height is reached, it is often difficult to fill in the top and maintain the required height.

All formal hedges should be slightly wider at the base and slope in to the top to maintain growth low down. Once a hedge becomes bare at the base through faulty pruning, or because it has been smothered by weeds or garden plants, it is almost impossible to force new growth. Trimming of hedge tops is a matter of personal preference, for rounded, flat, and pointed finishes are equally good.

The time for clipping depends on the plants used. Most evergreens should be trimmed every 6 to 12 weeks during the growing season and conifers more often. Frequent light clipping is far better than one or two hard trimmings a year. The hedge will remain in better condition and will not tend to get larger and larger each year.

Hedge plants such as abelia and escallonia may be trimmed less frequently to take advantage of their profuse flowering habit. Escallonias should be trimmed after their main flowering period, but abelias should be left until spring, as the coloured bracts which follow the flowers make a bright show in the winter garden. Formal neatness is sacrificed, but the effect is worth while.

Plants such as Tecoma capensis with a semi-climbing habit of growth do not produce rigid upright frameworks of branches, and are unsuitable for heights above 3ft. unless they are supported. Strong wire fences with very durable posts set in the centres of the hedge rows are the most suitable supports.

Pests and Diseases

Some hedges are good breeding grounds for a number of pests and should be sprayed at the same times as other susceptible plants in the garden. Thrips and scales are particularly bad and can seriously disfigure or debilitate hedges, and there is little hope of keeping other susceptible garden plants free of them when an infested hedge acts as a source of infestation. Fungous troubles are usually not serious.

Garden Work for July

July is the best time for planting, pruning, and winter spraying of roses. The plants should be put into their permanent positions as soon as possible after they have been received from the nursery. If planting must be delayed because of soil or weather conditions, the sacking round the plants should be untied and the plants heeled in in a sheltered place.

Planting Roses

It is desirable that the bed be prepared several months before planting time, so that it is consolidated and the

organic matter has decomposed to a suitable state. The planting hole must be sufficiently large to take the roots of the rose fully spread out, and deep enough to bring the bud union just below the surface of the bed. When planted the roots should normally be covered with not more than 6in. of soil, and it may be necessary to have the bud union higher above the soil surface to achieve this. A dressing of 4oz. of blood and bone should be worked into the bottom of each hole.

Where standard roses are being planted the stake should be driven into the hole before the plant is placed in position. Stakes made of angle iron and painted dark green or brown are more durable and quite as attractive as wooden stakes. All stakes for standard roses should be set so that the tops are at a uniform level, which should be just below the bud union.

In windy areas the staking of bush roses should be considered, as no plant can thrive while swivelling around on its stem. Old nylon stockings are excellent for tying, and it is important that one of the ties should be close to the head of the plant to prevent damage and the possibility of its snapping off in strong winds.

Where roots have been damaged they should be pruned back into firm wood. When the plant is set in position one or two spadesful of soil should be spread over the roots and the plant lifted slightly. If this operation is repeated, the soil will be well worked in among the roots. When the hole is nearly full the soil should be firmed by tramping. Finally, more soil should be added, tramped again, and levelled off. In heavier soils the tramping may be omitted at planting, but should be done in spring.

Rose Pruning

Contrary to a popular belief, rose bushes usually are not pruned when they come, from the nursery, and so pruning should be done at the normal time.

In warmer northern districts, where there is little danger of frosts, pruning should be completed during July. In colder districts it is best left until August, so that growth does not begin until the risk of damage by late frosts is reduced. Pruning secateurs must be sharp so that clean cuts can be made. This is most important in helping to prevent the serious attacks of “die-back” which are prevalent in New Zealand. Pruning cuts should be made to an outside bud, the cut sloping from {-in. to Jin. above

the bud on the bud side to a point level with the bud on the opposite side.

The first task when pruning roses of any type is to remove all dead, diseased, or crossing branches. Watershoots or vigorous autumn growths can be completely removed, but if they add to the framework of the plant, only the seed pods should be removed. Cutting into unripe wood may induce die-back, and this wood should be removed entirely or left unpruned until after flowering.

Newly Planted Roses

Newly planted roses should be pruned as follows. The widely used bush roses of the hybrid polyantha and hybrid tea types should be pruned back hard to an outside bud. Any weak shoots should . be removed entirely. Species and miniatures should not be pruned as severely, but should be trimmed to correspond with any necessary root trimming. Climbers should not be pruned severely, but should be neatly recut above the top bud. Hard pruning may induce a climber to revert to the bush form of growth.

Bush Roses of Hybrid Tea, Tea, and Hybrid Perpetual Types In the past severe pruning has been widely advocated for hybrid tea, tea, and hybrid perpetual types of bush roses, but the advantages of a less severe pruning are being realised. Growths should be shortened back by one-third to half their length. Very vigorous varieties such as Peace should be pruned more lightly and weaker growers should be pruned more severely. Standards of the same type should be pruned similarly but a little more severely.

Bush Polyanthas, Floribundas, and Grandifloras

The pruning of these types entails the removal of much of the wood which is more than a year old and a slight shortening back of the new wood. With standards pruning should be more severe.

Climbing Roses

The aim should be to replace as much flowering wood as possible with strong shoots produced last summer. Where older wood must be retained the side shoots should be cut back to two buds. All growths should be tied down as close as possible to a horizontal position. It will be found easiest if all old ties are removed and the shoots placed afresh.

Climbers of the Paul’s Scarlet type need little pruning other than the shortening of the laterals. Ramblers ®f the American Pillar type, which have one flush of. blooms each year, should be pruned . after flowering by removal .of ~ branches which have flowered. The new growths can then be tied in place. z

Winter Spraying Where scale insects are prevalent on the branches a spray of winter oil, 2 pints to 4 gallons of water, should be applied. To assist in the control of black spot fungus, immediately after pruning or 2 weeks after the application of winter oil a fungicidal spray should be applied. Thiram, Bordeaux mixture, or copper oxychloride sprays are quite satisfactory. Seed Sowing in the Glasshouse In a heated glasshouse July is the month for sowing seed of plants which take a long time to grow. Sow asparagus fern, making sure the seed is fresh, tuberous begonias,' streptocarpus, and Saintpaulia ionanthe. As

seeds of these plants are very small, they should be sown on well-sifted soil and not covered by any additional soil. The seed box or pot should be covered with a sheet of glass. Pot Plants The growing of pot plants is adding much interest to the lives of people who do not have a great amount of time for gardening or the replenishing of the floral decorations in the home. It is especially a pleasure at this season of the year, when flowers are not plentiful. A brief resume of tasks with these plants for July is given here. Achimenes: Pot the rhizomes and start them into growth.

Cyclamen: A light topdressing of a balanced fertiliser may help prolong the flowering season. Remember to use warm water and remove the flowers with a tug. Heliotrope (cherry-pie): Cut back and start into growth. Hoya carnosa:' Keep dry and rested at a cool temperature of 50 degrees F. Lippia citriodora (lemon-scented verbena): Prune back to old wood. Repot, if necessary, into a rich compost. Pinch back growing tips as necessary until December. Impatiens sultani (balsam): Keep fairly cool and dry during the rest period, July to September. Monster a deliciosa: Keep fairly dry. Primula obconica: Do not place in draughts, give adequate light, and water carefully from the bottom because of the plant’s susceptibility to collar rot fungus. Streptocarpus hybridis: Start plants into growth and sow seed. Vallota purpurea (Scarborough lily): Start bulbs into growth. Variegated foliage plants: Plants of this interesting and varied nature should be put in a more sunny position during winter to intensify their markings.

Cacti and Succulents Lithops may begin to shrivel at this time. This is natural, and they should be left quite dry. Other plants from which water should be entirely withheld are opuntia (the prickly pear), and aloes. Such plants as phyllocacti, epiphyllums, echeverias can be given one or two waterings this month as long as the water is lukewarm. The echinopsis or “sea urchins”, a very hairy and free-flowering group, should be kept cold, but they like a little water. These are some of the most easily grown of the cacti and are good plants for beginners. Cloche Gardening Though cloches are not particularly artistic in flower gardens, by their use it is possible to extend the flowering season. They can be used profitably where an area of flowers is set aside for cutting, and at present could be covering the following plants:— Freesias sown or planted in February and now about to bloom. Daffodils, iris, narcissi, and tulips planted in March and cloched last month. Gladiolus planted and cloched in late May.

Lily of the valley planted in autumn cloched in midwinter of the second season, and now being sheltered for flowering next month. General Work for the Month Consider the drainage of lawns. Aeration with a fork could be done now if this is necessary. Further levelling for spring sowing should be attended to. Compost heaps completed in autumn will probably be ready for turning. Check all plant labels. An excellent selection of durable metal tags is available at reasonable cost. Beds of plants for spring display can be lightly forked over to aerate the soil. .. Give some protection to winter roses Helleborus nigra and H. orientalis and to Iris ungicularis (stylosa) as the flowers emerge. Dust around the plants with DDT or lindane or use a metaldehyde bait to destroy slugs and snails, which can be most destructive to the flowers. Check supplies of fertilisers, seeds, tools, and spray materials and order more if required for the coming season.