Home & Building, Volume 12 Number 6 (June-July 1950)
the cultivation of perennial plants
Modern Hybrid Lupins — "Happiness" (Wine Red), "Northern Lass" (Sky Blue and White), "Downer's Delight" (Bright Pink and Carmine), "Torchlight" (Deep | Pink and Flame Red), "Gold Crest" (Yellow, Shaded Orange and Terra Cotta), "Chocolate Soldier" (Mahogany and Yellow), "Felicity" (Lilac Mauve), "Chelsea Blue" (Pale Blue).
In the cultivation of perennial plants a matter of the highest importance is the tillage of the soil. This applies with equal truth to every class, whether shrub, perennial or biennial, and in the main to the entire range of annuals also. But, despite this truism, it is a matter too often neglected, or the work at least only indifferently performed. If an amateur specialises in Roses or Sweet Peas, the invariable rule is so to make a beginning that success at the very outset would appear to be more than half assured. The soil is so thoroughly trenched and matured, that the operator has the supreme satisfaction of knowing that he is doing the work rightly and well and, that being so, he is entitled to look for a fair return for his labours. Generally, he is not disappointed and a full measure of success is the reward of his enthusiasm. In his first dealings with the perennial flower border the amateur is not always so enthusiastic as he is in the case of Roses or Sweet Peas, but the former demand it as much, and repay it as fully, as the latter. In any case the old adage "well done is always done" must apply for once a border is well prepared the one great obstacle to success is removed. Conversely, "badly done is never done" and the ill-prepared border is a source of dissatisfaction and an eyesore for a long time. Moreover, such a border has sooner or later to submit to preparation, and naturally the deferred work is more costly and slower than if undertaken at first. Obviously then the due preparation of the soil must be regarded as the first step. For treatment an entirely new piece of ground exists in the mind's eye. It may be a portion of a shrubbery border, a poaching on the preserves of the kitchen garden proper, or what often happens—a piece of new ground is being taken into the garden and awaits
treatment. The shrubbery border will invariably be found in a poor impoverished state owing to the long tenure of various shrubs. The first thing to do would be to rid the soil of every vestige of root and root fibre, grubbing them out, and making a bonfire of the materials on the spot, together with any rubbish that might be at hand. The ashes from such fires are rich in ammonia, potash and other salts, and by strewing them evenly over the surface, the soil would be receiving, if in a new form, some of the essentials of plant life long since removed. Such a border will require the deepest trenching and heaviest manuring to get it into good heart. Should the soil be very light, cow manure, whether comparatively fresh or well decomposed, will be the best—best not for high manurial value so much as for its cool, long enduring, moisture retaining properties. A six inch surface dressing of heavy soil thoroughly incorporated with the light soil would help to restore the soil to the original fertility, while making a medium for plant cutlivation bordering on the ideal. Heavy retentive soils would in addition to trenching, require sand, grit, leaf soil and light manure to render them porous and open. The drainage too, should be made perfect, A more efficient aeration of the whole mass of soil would be secured by throwing it roughly in high ridges for the winter, an operation which at once insures a more complete drainage, while exposing the maximum to the re-vitalising influences of frost and air.
Trenching is but another name for double digging. Its special office is to deepen and improve the soil, to render available a greater depth of material, aerated and enriched to sustain plant life. One method of trenching is to mark off a strip of ground two feet or so in width, and excavate it one spade deep. Transfer this soil to the other end of the border. Now dig or fork over the subsoil, incorporating any enriching material such as well-rotted manure, leaf mould etc., during the operation. With the first trench open, a width equal to the first should be marked off, and the top soil turned over onto the already dug subsoil. Now dig over the subsoil as before, and continue to the end of the border where the soil previously deposited will fill in the cavity which you will have if the work has been done evenly. Now give the border a good dressing of thoroughly well-rotted manure on the surface and dig or fork it in. In about a week's time give the bed a dressing of lime and fork it in at once. The work of trenching should be done in the early Autumn, where possible, so that the ameliorating effects of frost, rain and air, can exert their fullest influence upon the soil. A final step in this important matter of soil preparation is to fork the soil over at every available opportunity when it is in a nice workable condition but never when wet or sticky. If the soil is heavy ashes from the garden fires, or any lightening material such as sifted leaf mould should be applied at this time.
When to Plant: Perennials have their own season for starting, both with root activity and stem growth. Some, too, are almost perpetual in their rooting, continuing to page 61produce root fibres during a greater part of the year. The border Perennial Phloxes are an instance of this. Others however, such as Iris, Paeony and Helleborus, produce root fibres at fixed intervals. The first-named set may be planted over a considerable period. The others can not be so treated. This is due to the fact that only two sets of roots are produced by these plants each year, and the loss of the primary set—the basal roots of Autumn—which also entail the loss of the secondary set, appearing normally in Spring, the plant is thrown on its own resources for probably a whole year. This gives rise to a general weakness in the whole plant, and recovery is very slow. In the main, however, that large class of plants which figure under the heading of perennials are of so vigorous a nature that they submit to planting either in Autumn or in Spring. A principle involved in the latter, however, is that the work be timely done so that the subject has the advantage of becoming established before dry weather sets in. In a general way the majority transplant quite well just prior to new growth appearing. The Perennial phlox, because of this continuous rooting and the loss of stamina which late planting involves, I prefer to plant in early Autumn. In this way the plants obtain a good hold of their new positions before Spring.
The Fallacy of the big clump. Let me emphasise this, because to the beginner there is no more fatal error. The youthful plant is capable of much better work. Why? Because its every shoot and bud has opportunities for developing, whilst those of the big clump are hopelessly hemmed in on every side. The specialist of the Chrysanthemum obtains his best results not by employing the shoots of worn out stock but, from young plants periodically increased — refreshed, renewed, re-invigorated. The day of neglect or of indifference of the perennial border is past. It is not sufficient to plant and leave the rest to chance. We will reap just in proportion as our labour has been assiduous and enthusiastic.
Staking and Tying—are small matters of great importance. They show at once the taste, intelligence or indifference of the owner. Badly tied specimens rob the plants of all beauty and charm, and bundle tied examples are ugliest of all. Every plant in nature has a certain more or less well-defined contour of its own; the aim of the gardener should be to imitate it as nearly as possible. In good gardens the proper staking of plants receives seasonable as well as intelligent treatment. The habit of the plant is anticipated and a good natural result ensues. This is done, say, in the case of Michaelmas Daisies by placing a number of stakes to each specimen during the early stages of growth, so that with the latter completed, the stakes are quite or nearly obscured from view. In staking no stick need reach to a greater height than two-thirds that of the plant. The top spread of the plants should receive due consideration. For such as these it will be necessary to insert the stakes near the root stock of the plant, setting them at an outwardly reclining angle to suit the growth of the plant. A golden rule would be never to stake unless it is necessary. Staking should be resorted to to preserve, not to mar, beauty. Elegant Lobelia plants such as aquilegias should seldom be staked; the play of the flowers consequent upon the prevailing breeze but adds to their many graces. Stakes, too, should be light and rendered as inconspicuous as possible.
Watering. This, in the case of Spring planted examples, is a matter of importance, and again for subjects approaching the flowering stage in times of drought. In all cases where necessary the work should be thoroughly done,page 63
a complete saturating of all the surrounding soil. In watering with a hosepipe it is not necessary to direct the full force of the water at the middle of a plant. It is the soil that requires saturation, though the plant will be greatly refreshed by a shower bath at the end.
Special Subjects. Herbaceous Paeonies, The soil cannot be too deeply or too well prepared, with plenty of manure worked in. The roots will descend quite 3 ft. in an established plant. Copious supplies of liquid manure should be given and plenty of water at all times.
When to plant. The best months are March and April, and the earlier the better. This is of vital importance to the future well-being of the plant. How to Plant is equally important. To plant big clumps of Paeony intact is an almost fatal mistake. The right kind of plant is that composed of three to five crowns. At planting time the crowns should be buried at least two inches below the surface. Plant about 2 ft. asunder, and 3 or 5 make a good group. They look splendid planted in conjunction with Liliums. How to increase the Paeony. First wash away the soil from the roots. This will reveal the solid root stock and the thong-like tap roots as they cross and recross each other. If the plant is large lay it on its side and insert two garden forks back to back driving them into the root stock two inches below the crowns. Now wrench asunder by pressing the forks outwardly in opposite directions. To cut through the root-stock with any sharp instrument is as bad as it is wrong. The Delphinium. The best effects are produced by massing the plants in beds or borders, a bold group of one colour only. In grouping the bolder growing sorts should be arranged 2 ft. asunder; the more slender growing sorts—Belladonna and the like— requiring about 11/2 ft. of space. In the matter of cultivation the delphinium delights in rich soils, well and deeply prepared. It takes most quickly to light, well-drained, loamy soils, though bolder and more enduring perhaps, in soils of stronger character. Poor, hungry and shallow soils are starvation; wet, tenacious clays doom. Heavy soils should receive an ample dressing of lime, also wood ashes and leaf mould; anything indeed that will assist porosity. The best planting season is Spring—August or September —when the new growth is appearing. The best type of plant is that from the open ground. Keep the crown 2 inches below the surface soil in planting. The Delphinium is increased by seeds and division. Sow the former in shallow drills in the open ground soon after it ripens. Division should be effected in Spring, the point of a sharp knife—the plant meanwhile lying on its side after being freed of all soil—inserted in the root stock below the crown being the best. The work requires care to insure the presence of root fibres and a good crown to each division.
Pests. Its greatest pest is the slug; often more troublesome on heavy soils than on light ones. The pest secretes itself in the crown of the plant during winter and early spring, and may be dislodged, or discouraged by frequent sprinklings of soot, by coverings of fine ash, and dustings of slugene. Mildew can be kept in check by spraying with lime sulphur or sulphide of potassium using 1 oz. to 3 gallons, dissolving it first in a little hot water. The Perennial Phlox. The phlox is well suited for making fine colour pictures. It should always be boldly massed, never planted feebly or as isolated specimens. Preferably also the colours should be used alone. The plant is free rooting and has a voracious appetite. A lover of cool moist soils, in summer time the borders may be practically flooded with water twice a week to the benefit of the plant, and to the full development of its high panicles of flowers. Thepage 65
plant luxuriates in a free rich loam, and the greater the depth, and the deeper and richer the cultivation, the better the results.
When to plant. Preference is given to early Autumns, though the plant being a perpetual rooting subject, is by no means exacting in this respect. The earlier the planting is done, the better the hold obtained upon the new soil, and the better the results. Propagation. The only method calling for comment here is by division. Division of the old plants can be easily effected by means of two forks. Propagation of perennial plants. The propagation of perennial plants is effected by seeds, cuttings, division of the root-stock, and by root cuttings each of which has a value of its own. Seeds. The best time for sowing, locally, is from December to March. Many will then flower the first season. The larger seeded subjects such as Lupin, Perennial-Pea, Iris, Kniphofia, Adonis, or quickly vegetating subjects like Anchusa, Gaillardia, Aquilegia, Iberis or Candytuft and Alyssum are best sown either in drills in the open ground, or with the protection of a spare frame. Perennial Phlox, Iris, certain of the Perennial Anemones including A. Hepatica, and others very slow to vegetate, should be sown in a place apart, or in pans or pots, so that they may be kept for a long time. All small seeds are best sown in pans or boxes. Seeds of large size should be covered nearly half an inch deep; the smaller seeds should be merely covered their own depth with very fine soil or sand. Primulas, and Polyanthus, working by their own weight into the interstices of the soil, are often best without any soil covering at all. The seeds of these, also Delphinium and Aquilegia, soon lose vitality if kept long out of the soil, and many other instances might be given did space permit. By Division. Certain classes of plants may be divided with the greatest ease, others require considerable care. Michaelmas Daisies, Trollius Iris, Helenium, Arabis, Aubrietia, Phlox, Lychnis, and Pyrethrums are instances ofpage 67
plants that are readily pulled to pieces or divided by inserting the point of a strong knife, below the ground level of the shoots. For Paeonies and Kniphofias and, indeed all plants having stubborn root stocks, or those whose roots are crossed or contorted, I know of no better way of dividing than inserting two small hand forks back to back in the rootstock below the crown and wrenching them outwards in opposite directions. This has the effect of rending even with the grain of the root stock and little or no loss is entailed. Blunt and sharp cutting implements, the spade, chopper, hatchet or edging iron, cutting through destroy i both root and root fibres. There is no better way of spoiling the plants and their, roots, than by chopping and hacking —the ordinary methods of the inexperienced—with such tools as these. By Cuttings. The chief value of cutting propagation lies in the greatly increased numbers of young plants thereby assured, which to the specialist is a great asset. Cutting of soft wood subjects, such as Perennial Phlox, Perennial Sunflowers, Penstemons, Perennial Candytuft and others having more or less solid stems, are best made to a joint i.e. that portion of the stem from which usually the leaves emerge. By removing the lower leaves and cutting in a horizontal direction close to the base of the leaves, the joint is revealed, at least in part. Hollow-stemmed cuttings, Delphinium and Pyrethrum, for example, must have a heel attached—a heel is the, piece of the older stem to which they are attached—and are best with cold frame treatment. But whether of joint or heel, the cutting should be always of a youthful nature. Portions of growth already hardened by age or exhausted by flowering are of but little use to the propagator. To avoid these, certain plants should be cut back after flowering, and thus made to produce the right material for cuttings.
By Root Cuttings. This consists of detaching portions of the roots of plants, making them into uniform lengths of about 11/2 inches, and inserting in rows in shallow boxes or pans of sandy soil. The top of the cutting should be just exposed. The Winter season, May to August is the best time. A temperature of about 50 degrees is best for the cuttings. Anchusa, Phlox, Stokesia, Gaillardia, Statice, Eryngium, Oriental Poppy, Japanese Anemone, Primula, and Senecia are a few among the many which may be increased in this way.