The Perennial Flower Border in Spring

New Zealand Journal of Agriculture, Volume 89, Issue 1, 15 July 1954, Page 87

The Perennial Flower Border in Spring

THE perennial border, though an established feature in the garden, can be redesigned • every few years, thus providing a pleasing change. When well prepared and planned it will give a display of flowers throughout summer. In this article K. H. Marcussen, Horticulturist, Department of Agriculture, Christchurch, describes the establishment of a perennial border and the work that should be carried out in an established one during spring. The cultural recommendations can also be applied to the mixed border, in which most flower gardeners grow some herbaceous perennials. Flower garden work for August is dealt with by M. Joanna Lockie, Horticultural Instructor, Department of Agriculture, Auckland.

K/fOST of the plants used in the •‘•’-I perennial border are commonly termed herbaceous perennials. They produce fresh top growth every spring and this dies down after flowering or dries off during winter if not removed. The crowns of these plants are generally quite hardy and only in the coldest districts is winter protection necessary. Most are fibrous rooted and will, after a few years, grow into tight clumps, in which the older portions in the centre get little nourishment or moisture as compared with the outside portions. It is consequently necessary to replant them every 3 or 4 years to get the best results. There are, however, some with fleshy roots, such as gypsophila, peony, lythrum, platycodon, and oriental Poppy. Most of this type dislike disturbance and may “sulk” for a season after being transplanted. If such plants are doing well and not showing signs of impoverishment, they are better left alone. These characteristics should be kept in mind when a new border is being laid out or an old one rearranged.

Selection of Site In the average flower garden there is not much choice for the site of a herbaceous border. It generally has to follow one of the sides of the garden and will often be in front of a boundary fence or a hedge. However, it is important to consider the aspect, as one side , of the garden may mean a cold and wet position with little morning sun during spring when the plants begin growing, and the other side may provide a situation where the plants are bathed in sunshine during the first half of the day. The ideal location is one with an easterly or northerly aspect, well sheltered, but away from trees and vigorously growing shrubs whose roots will compete with the herbaceous plants for nourishment and moisture. The width of the border will vary greatly, but less than 6ft. cannot be recommended if a good selection of plants is desired, as that will not provide enough space for variation in height; Bft. will allow much more scope. A border with walks on both sides can be made, but calls for much

greater care in planning, as generally one side will be in the shade of the taller-growing plants necessarily growing in the centre. For such a border a much greater width is desirable. A deep medium loam is best, but with good management either a heavy or a light soil can be used, provided drainage is adequate. Preparation of Ground When the site has been chosen and the edges of the border are determined preparation of the soil should begin without delay to enable natural settling of the bed before planting. Drainage is of great importance and must be attended to first, if required. Few plants like waterlogged conditions. Any perennial weeds such as twitch and docks must be removed, as it will not be easy to dig them up once the bed is planted. . The whole bed should then be dug over to a depth of at least . 2ft. If the subsoil is heavy, , this operation becomes very important. After the top spit has been removed the next layer should be thoroughly broken up and coarse organic material such as old stack bottom or half-rotted compost incorporated. The heavier the subsoil is the coarser this material should be and also the more liberally it should be applied to improve drainage and

aeration and so give better growing conditions. When the topsoil is being replaced as much fine organic material as is available should be mixed in to provide a good tilth. Liming will probably have to .be done, as most herbaceous plants prefer a neutral soil; 2oz. to the square yard is a safe application on most types of soil when a border is bein o, prepared. After a fortnight fertiliser should be applied in the form of basic slag at 6oz. to the square yard or superphosphate at 4oz. to the square yard. Basic slag is preferable for heavier soils. The border should now be left until ready for planting, except for an occasional hoeing to keep the soil open and to suppress any weeds that may germinate. Planning the Arrangement Next in importance to the preparation of the soil comes the laying out of the border. This job demands a lot of consideration and can be carried out in the comfort of a fireside chair. A plan of the border should be drawn on paper and as decisions are made regarding the various plants to be used the positions should be set down. A border may be planted in one colour, but it is then very difficult to provide a display . throughout the season, and the mixed border is usually favoured. The selection of plants may depend on source of supply. Many home gardeners establishing a perennial border are able to obtain a number of plants from friends. Among these will probably be plants like aquilegia, delphinium, golden rod, helenium, helianthus, and shasta daisy, and perennial types of aster, phlox, and scabious. These plants should be spaced in groups at intervals through-

out the border to give substance and a bold effect. Though the height of plants .is generally graduated with the tallest at the back, this should not be done too regularly. _ It gives a much better effect if this rise in height is brought about by placing clumps of varying height irregularly, instead of placing them in definite lines along the border. It is better to place a few plants of the same variety together in a clump than .to scatter them individually through the border. Apart from height, colour combina-

tion and contrast are of great importance and must be given attention. The period and length of flowering are other factors that must be taken into consideration. Proper placing in relation to these factors will determine the display, of colour throughout the season. Furthermore, some of the herbaceous plants prefer shade and moist conditions. These can be set in positions which are not suitable for most other plants. Distance between groups will vary according to the height and spread of

the plants. As a general recommendation plants growing up to 18in. high should be Ift. apart, those 18in. to 2|ft. high 2ft. apart, and those 2|ft. to 4ft. or more not less than 3ft. Between individual plants in a group distance should range from 9in. to 18in. accordingly. If all plants must be purchased, it may be wiser to concentrate on a smaller border for a year or two, after which many plants will be large enough to be divided. Another solution would be to plant sections with annuals temporarily and later fill them with perennials. Bulbs, dahlias, and chrysanthemums can also be used in the border to give a longer period of flowering. Planting If the ground has been well prepared and a good plan has been made, planting is a small job. When planting is done during spring it should be completed before growth begins. Satisfactory planting cannot be done if the ground is too wet. If soil clogs on the boots, it is better to keep off the border until it has dried up and heel in any plants that may arrive. Working from the plan, the gardener should proceed to mark out where all the plants are to be placed and begin planting from one end, and so avoid tramping over the finished area. The roots of each plant should be checked over and any damaged or exceptionally long pieces cut off cleanly. The hole should be dug big enough and the soil packed firmly round the roots, with the crown of each plant about Im. below soil level. Any plants that appear very tender can be lightly mulched with straw or other light material. Once the border has been planted a copy of the plan should be kept for reference. It will then be possible to check the identity of any plant, whether it is flowering or not. Snails and Slugs Snails and slugs must be watched for when the plants begin growing, as the young, tender shoots may be considerably damaged by these pests. The best control is a bait of bran and metaldehyde. This is made by mixing loz. of metaldehyde powder with 2>lb. of bran moistened with molasses. Small heaps of this should be placed near the. haunts of snails and slugs in the evening. Established Borders in August In many home gardens the herbaceous border will have been mulched in autumn after it was cleaned up both as a manurial measure and as a protective covering during winter. This mulch should now be incorporated in the topsoil, where it will improve both tilth and water-holding capacity of the soil. Division Where division of plants is desirable and this has not been done in autumn it should be attended to before growth begins. After the plants have been lifted the ground should be dug over and enriched with organic material, as described for a new border.

When the plants are being divided it is best to tear them apart with two forks placed back to back or to sever them with a sharp knife. Always discard the centre and woody portions in favour of the vigorous shoots nearer the outside of the clump. The plants should not be allowed to dry out; if they have to be left out of the ground for any length of time, they should be kept out of the sun and wind and either sprinkled with water or covered with wet scrim. ■ Thinning out When it is not necessary to divide plants it may be advisable to reduce

the number of shoots and so regulate the amount of growth. This will e ns u r e stronger and better plants. Make sure the shoots are cut off close to their base; otherwise this cut may only act as a “stop” and result in additional new shoots developing. Cuttings To increase some of the slower growing plants by cuttings is best done when the plants are starting to grow. Select vigorous plants and cut some of the shoots off when they are about 4in. long. Remove the leaves and

trim the base just below a node and insert the cutting in sandy soil in a propagating frame. If a frame is not available, a few cuttings can be accommodated under a preserving jar. They should be kept well watered and closed up for a week to 10 days and shaded from direct sun. From then on ventilation should be gradually increased and in a few weeks root growth will begin. Treatment with one of the rooting hormones will assist, but the use of these will not justify less care of the cuttings while they are forming roots.

Fertilisers Even if a mulch has been dug into the border, an application of a complete fertiliser at this time of the year will be of great benefit to the plants and should be given at 2oz. to the square yard. Such a fertiliser may be made up of 3 parts by weight of blood and bone, 2 parts of superphosphate, and 1 part of sulphate of potash.

Some Herbaceous Perennials! their Flowering Season, and Range of Height. Colours Vary in Varieties

Spring Alyssum saxatile Ift. Iberis .. .. Ift. Arabis .. . . ft. Primula . . ift. to Ift. Aubrietia . . |ft. Saxifraga crassifolia Ift. Doronicum .. Ift. to 4ft. Saxifraga cor difolia lift. Late Spring and Early Summer Aquilegia . . lift, to 3ft. Nepeta mussini Ift. Geum .. .. Ift. to 2ft. Paeonia .. . . lift. to 3ft. Heuchera . . Ift. to 2ft. , Papaver orientate Ift. to 3ft. Iris germanica . 2ft. to 4ft. Physostegia '. . 3ft. Iris laevigata Polygonatum .. 2ft. (Kaempferi) . 2|ft.. Chrysanthemum coccineum Linaria .. . . 2ft. to 3ft. (Pyrethrum roseum) Lupinus . . 2ft. to sft. 2ft. Summer Achillea .. lift, to sft. Geranium .. . Ift. to 3ft. ■Aconitum ... 2ft. to 6ft. Geum .. .. Ift. to 2ft. Anchusa . . 2ft. to sft. Gypsophila .. lift, to 3ft. Astilbe . . . . lift, to sft. Helianthus . . 3ft. to Bft. Bocconia cordata 6ft. Heliopsis .. 3ft. to sft. Campanula . . Ift. to sft. Hemer ocallis . . 3ft. Canna . . . . 2ft. to sft. Hosta (Funkia) lift, to 2ift. Centranthus .. 2ft. Inula .. .. 2ft. to 6ft. Chrysanthemum Iris germanica . 2ft. to 4ft. maximum . . Ift. to 3ft. Linum .. . . Ift. to 2ft. Coreopsis .. Ift. to 4ft. * Lupinus ... 2ft. to sft. Dahlia . . .. 2ft. to sft. Lychnis . . Ift. to 3ft. Delphinium . . 2ft. to 6ft. . Lythrum . . 2ft. to 3ft. Dianthus .. if t. to 2ft. Monarda . . 2Jft. Dictamnus . . 3ft. Nepeta mussini Ift. Echinops . . 2ft. to sft. Oenothera . . Ift. to 2ft. Erigeron .. Ift. to 2ft. Paeonia .. .. lift, to 3ft. Eryngium ... 2ft. to sft. Pentstemon .. lift, to 3ft. Gaillardia . . 2ft. Phlox .. ■. . Ift. to 4ft. Galega .. . . 2ft. Platycodon . . Ift. to 2ft.

Potentilla .. Ift. to 2ft. Tradescantia .. 2ft. Scabiosa .. 2ft. to 4ft. Verbascum . . 2ft. to 4ft. Sidalcea . . 2ft. to 3ft. Verbena . . Ift. to 3ft Statice .. . . Ift. to 2ft. Veronica . . Ift. to 3ft Thalictrum . . 2ft. to 4ft. Late Summer and Early Autumn Aconitum .. 2ft. to 6ft. Kniphofia .. lift, to sft Anemone japonica 3ft. Tritonia .. 2ft. to sft. Aster .. . . Ift. to sft. Nepeta mussini Ift Chrysanthemum Ift. to sft. Pentstemon .. l|ft. to 3ft. Dahlia ... . ... 2ft. to sft. . Chrysanthemum coccineum Delphinium .. Ift. to 6ft. (Pyrethrum roseum) Echznacea purpurea 34ft. ' , 2ft Helenium .. 2ft. to sft. Rudbeckia ' . . 2ft. to 6ft. Helianthus .. 3ft. to Bft. Solidago . . 2ft. to sft. .■ Autumn Aconitum . .. 2ft. to 6ft. Physalis alkekengi 2ft. Aster . . . . Ift. to sft. Rudbeckia . . 2ft to 6ft. Chrysanthemum Ift. to sft. Solidago .. 2ft to sft Helianthus . . 3ft. to Bft. Schizostylis . . 2ft Kniphofia .. IJft. to sft. Winter Helleborus .. Ift. to 2ft. Petasites fragrans Ift Iris unguicularis Primula .. iff to'llft (stylosa) .. lift. Schizostylis .. 2 ft Kniphofia .. 3ft. to sft. Some Herbaceous Perennials which Will Tolerate Much Shade Acanthus .. Ift. to 4ft. Cimicifuga . . 3ft to sft Aconitum . . 2ft. to 6ft. Hosta (Funkia) lift, to 24ft Anemone japonica 3ft. Helleborus .. Ift to 2ft Astilbe . . . . lift, to sft. Primula . . iff’ to lift

Garden Work for August

August may be considered the beginning, of the new gardening year, and though it is too early to start sowing seeds anywhere

except in glasshouses or frames in northern districts, it is the month for putting everything in readiness for smooth working when the busy spring season starts. Flower seed should be bought now ready for September sowing. If this is left until later, the range of varieties narrows down, and though there will be supplies of the more common annuals, it is disappointing not to be able to try out some newer kinds and varieties. Good seed should be bought, as the difference in cost is small compared' with the difference in results. Care and attention cannot improve the plants obtained from poor seed. Poor plants take as much room in the garden as good ones and need every bit as much care and attention, yet the final result will remain indifferent. Nemesias and pansies are two of the earliest sowings which can be made. Early sowing in boxes will give flowers in October and November. Preparation of seed boxes for the glasshouse is the same as for seed boxes used outside. A soil mixture containing 2 parts of soil, 1 part of peat, leafmould, or well-decayed compost, plus 1 part of sharp river sand is prepared by mixing the 3 ingredients thoroughly together. Raw compost in a seed box can do more harm than good. Each box should have cracks along the bottom to aid drainage and should have Jin. of rubble from sieved soil, scoria, or some other form of drainage beneath the soil mixture. Faulty drainage, combined with overwatering, is a common cause of failure in raising seed. Soil in the boxes should be firm, and in particular the corners should be made firm and level with the remainder of the soil. If this firming and levelling are not carried out properly, the first time water is applied to the box the corners sink, leaving a hump in the centre of the box which is difficult to keep moist, and the corners themselves are kept too wet. When the box is properly prepared it may be steeped by lowering it into a container of water, with the water no higher than the level of the soil; otherwise the topsoil floats off. Once dark patches show through, the box should be lifted out and left to drain. Seed may be sown next day. Alternatively, the prepared box may be watered overhead, care being taken not to cause flooding, which again is likely to disturb the topsoil. The box should be left to drain a few hours before sowing.

Seed should be distributed evenly, and not too thickly over the soil and covered its own depth with very fine soil. Poppy and antirrhinum seed, which are very fine, barely need covering. Lupin seed, which is larger, requires a deeper cover of soil. Fresh seed should be used in preference to old seed, as it usually germinates more freely. Seed boxes should be covered with glass and paper. The glass needs turning every day or the condensation which forms should be wiped off. Once germination occurs the paper should be removed, and the glass soon after; otherwise the seedlings become spindly and drawn. Watering should be carried out sparingly and with a fine rose on the watering can. Excess moisture,

either on the foliage or in the soil in humid weather particularly, or where seedlings are very thickly sown, is likely to be a factor contributing to an attack of damping off, a fungous disease which is apt to cause havoc in seed boxes under these conditions. Prevention by ensuring that the box is well prepared, with good drainage and thinly sown seeds, is half the battle. Where damping off does occur healthy seedlings should be pricked out immediately into fresh soil. A full description of raising plants from seed in boxes is given in the June 1952 issue of the “Journal”.

Seed sowing outdoors direct into the soil must be delayed until soil temperature rises and the soil dries out more. For germination it is essential that air, moisture, and temperature conditions are favourable. While the soil, is cold and wet, even if the seed does germinate, the adverse conditions may kill or weaken the roots, causing the plants to die or stand still. Once the soil has warmed up not only should the germination percentage be

greater, but the resultant plants should be more vigorous. Gladioli . In warmer northern districts the first planting of gladioli may be made for early flowers. Early plantings require approximately 90 days from planting to flowering. Later plantings may take less. The variety also has some effect on the time taken to flower. Gladioli prefer a good, rich, wellworked soil with freedom from root competition, and in exposed positions particularly it is just as well to put the stakes in during planting, so that they are there when required.

Planting depths vary from 4in.. to Bin., depending on soil types; in lighter soils deeper planting is more satisfactory. As each planting hole is opened up with a trowel a handful of sand may be thrown in and the corm set on that. The corms most likely to give a good flower stem are those which are plump and thick through the centre. Cormlets may be sown now, about ljin. deep, to gain the benefit of a long growing season. Roses The pruning of bush and climbing roses is carried out now and should be completed by the end of this month. Pruning of bush roses is a straightforward job and consists of cutting out all dead and diseased material, all spindly and weak growth, and all spent flowering material. Once all this material is removed it is possible to remove crossing branches and to prune to keep the centre of the bush open. This is best carried out by cutting to a bud which points outward. Strong young growths should be retained in preference to older wood. Climbing roses are pruned, by the cutting out of weak or diseased growths and the shortening of the side shoots which have flowered to within two or three buds of their base. Strong young unflowered shoots only need their tips cut back slightly. Sharp secateurs should be used to ensure that each cut is clean and does not tear or damage the bark. All cuts should be made just above the position where a bud arises. Where buds are dormant or not pronounced the scar showing where a leaf has fallen gives a useful indication of the bud position. All prunings should be gathered and burnt. Not only are prunings extremely unpleasant to discover while weeding around the rose bed is being done, but they harbour fungous diseases and sometimes insect pests. After pruning is done, the rose bed can be lightly forked, and as roses are surface rooted, the working must be shallow to avoid damaging them. A mulch of farmyard manure, or where this is unobtainable a dressing of 4oz. of blood and bone plus 2oz. of superphosphate may be given before mulching with compost or lawn clippings.

This mulch will need renewing at intervals throughout the growing season. Whichever mulching material is used it should be distributed to cover the full extent of each plant’s roots and should not be allowed to touch the trunk. Immediately after pruning and before the new growth breaks a spraying of Bordeaux mixture should be given at 6|oz. of bluestone and s|oz. of hydrated lime to 4 gallons of water against the carryover of fungous diseases, particularly black spot. A Bordeaux spray of this strength can

be used only while there is no foliage on the bush. For later use when the bush is in leaf the strength of 4oz. of bluestone and soz. of hydrated lime to 4 gallons of water may be used as a protection against black spot. Where rust is troublesome a change should be made to lime sulphur in summer, onefifth pint to 4 gallons of water. Where rose scale is present on older rose wood a summer oil spray at the strength of 1 pint to 4 gallons of water may be applied, or the oil may be incorporated in the first Bordeaux spray. For climbing roses, where the spray cannot be applied to give an effective coverage on the side nearest the wall or support, when pruning is being done the canes can be untied and scrubbed with an emulsion of summer oil, 1 pint to 4 gallons of water. Sweet Peas Seeds of sweet peas may be sown in boxes in-frames or glasshouses for later planting out. As sweet peas do best on firm soil, the bed they are to occupy can be prepared now. It should be thoroughly worked and well enriched with decayed farmyard manure or compost added to the bottom spit. Sweet peas are gross feeders and like to get their roots well down. They do not like loose soil, so that preparations made in advance will allow the soil to consolidate before planting. A light dressing of lime may be applied after planting out. As slugs are particularly attracted to * young sweet peas, it may be necessary to use some slug bait around them. Metaldehyde tablets crushed and mixed with bran slightly moistened with molasses provide a satisfactory control. Small heaps should be set out and protected from rain by partially covering them with chips of wood or pieces of broken flower pots. Stakes or wire netting should be in position before the seed is sown. Soaking of seed may be done, though it is not particularly beneficial. If the seed is soaked, it must be sown immediately into damp ground; otherwise the seed which has been started into growth by the water will be dried out and killed. * ■

Shelter In many home gardens lack of adequate shelter is one of the principal factors limiting the garden display. Plants cannot do their best when constantly being buffeted by drying winds.. Roots worked loose in the soil soon dry out. New growth on shrubs is scorched and shrivelled and even older leaves develop a puckered look. It is still not too late to put in a hedge to form a breakwind. For coastal areas Corokia cotoneaster, Coprosma baueri (taupata), or flax will withstand salt wind. In other districts quick temporary shelter may be had by using tree lucerne or Albizzia lophantha. The albizzia and tree »lucerne may be sown from seed next month. For best results seed should be soaked in hot water and drilled into damp soil. With tree lucerne better results may be gained if soil collected from around other established tree lucernes is included in the drill. Albizzia is frost tender, so that its use is restricted to Auckland and the coastal areas of the North Island. Where these two hedges are trimmed from early days they create most satisfactory temporary shelter. With age, however, they open out, and borer attacks kill some of the branches, so that planting of a permanent hedge species should not be delayed. Where space is not a consideration Buddleia salvifolia makes a useful rough hedge. It stands coastal conditions and poor soil and will grow to 15ft. or 20ft. in 4 years. Cuttings of buddleia may be planted now, and in a year they should be up to 4ft. high. Cuttings should be made of vigorous, firm wood of last season’s growth and each one trimmed with a straight cut below a node, which is the position where a leaf bud arises. Depending on the distance between nodes, each cutting should be 6in. to Bin. long. Planting of the permanent hedge should not be a haphazard job. A good hedge takes years to develop and time spent on planting and maintenance ensures proper growth. A wellgrown hedge takes a few years to become a feature of the home surroundings. The hedge chosen should be one known to grow satisfactorily in the district and it should be suitable for the purpose. Abella chinensis, Escallonia exoniensis, privet (Ligustrum ovalifolium), and Lonicera nitida can all be trimmed to make neat hedges which do not become too wide and which can be kept at any height required. Pittosporum crassifolium (karo) is a suitable coastal hedge, but is inclined to open out at the base. Tasmanian ngaio (Myoporum serratum) is a quick-growing shrub also suitable for the coast, but the best shrubs to be used as a trimmed hedge in a seaside garden are taupata (Coprosma baueri) and Corokia cotoneaster. Around Auckland and frostfree districts Tecoma capensis makes a most satisfactory hedge; if it is to be grown to any height, it requires the support of a wire fence. Large hedge species such as acmena (Eugenia smithi), Chamaecyparis lawsoniana, and Cupressus macrocarpa may be suitable for farm and orchard shelter, but grow far too big for general use in small gardens. All photographs on page 88 except that of helianthus are by Douglas Elliott.