Gardening Notes

Hutt News, Volume 2, Issue 21, 17 October 1929, Page 9

Gardening Notes

THE HERBACEOUS BORDER.

In choosing a site for the herbaceous border, it is advisable to avoid a southerly aspect, or one in the vicinity of overhanging trees. Where possible, large trees should be at least 30 feet away. Peppers, Cedars, Pines, Crums, etc., are great consumers of water, and if adjacent to the border, the action of their roots will be detrimental to the smaller flowering plants. Shelter from the noTth and south-west winds is essential, and advantage should be taken of any breakwind or building that will afford such shelter. The ideal site is in open, sunny situation protected from the ground winds. As a rule, tie herbaceous border is seen only from one side, so that in planting, due eonsLleration must be given to that point. To obtain the best efforts when in bloom the taUer plants should be placed at the back and the dwarf varieties in front. A border containing herbaceous plants only, would be bare in winter and early spring, so that in planting for general effect it is necessary tp introduce some evergreen and deciduous flowering shrubs, and should the size of tie border permit it, dwarf palms may be included with advantage, As evergreen shrubs are used for Winter decoration they should be planned between the deciduos ones>, whi^lr, of course, are leafless in the winter. All these shnrbs are generally placed at': the back of the border; but with judicious pruning they may be kept -it any •height and given a position more or less to the front, at the discretion of the gardonor. At the back of the ioTder are placed the tallest perennials, next come the dwarf growing, hero ace ous .plants, and finally at the front, the an-, nuals and biennials. ( Most annuals re-' quire a good deal of attention, and this' can only be given when t-hey are placed in the front of the border; as a -rule, they do not thrive in the shade of otherplants. The best effects are obtained by planting annuals in masses, and herbaceous and perennial plants in jumps. Have *he various kinds well distributed throughout so that at tie end •. f the flowering season plants like Chrysanthemums will be able to come to the i rescue and save long gaps in the border. The arrangement of leoloars is a matter that I tiling might well be left to the individual taste. In the matter of watering, the.best results are obtained by overhead sprinkling, and the soil should bo well soaked whenever water is used. If this is done, and a Dutch hoe used to loosen the surface, the soil, if mulched, will not require watering again for a few days even in the driest SummcT. Merely watering the plants every evening only wets the surface and encourages the roots to come to the surface instead of sending fclem down "and making them independent of the dry weather. No doubt some amateurs think the/ have done splendidly when they see the paths and beds iooking moist anJ damp, but alas for the poor plants! Deep Cultivation, Moisture, air, food material and warmth are the necessary requisites for the good growth of plants, and though all of these may be present in abundance, yet, owing to the condition of the soil, ono or more may not be fully available to the growing plant, and poor flowers may be the result. When this is the ease, no matter how mxreh labour and money are expended on th-3 surface soil, little or no improvament is evident., and examination^ usually Teveals the presence of a hard stratum of subsoil at a greater or less depta below the surface. .This is known as a pan, and being practically impervious to water is consequently not aeratcl, and as a result, no plant roots penetrate it. Such, a subsoil has little or no communication with the soil above, and is, therefore, useless to plants. When it is broken up thoroughly and prevented from rapid panning again by the ntroduction of vegetable refuse, water percolates freely, air follows; and the roots of xthe plants have a greater depth at which to search for moisture and, therefore, for food material. Now, the fact that water percolates downwards from the soil to the subsoil does not necessarily imply that the zone of soil above the water table, i.e., the strata where the pore space is saturated, does not contain water, J or much water will be held in suspension in the soil. TShis suspended water forms a connecting link between the w.ater in the subsoil and the surface layers of the soi?, a connection which was not present when an impervious pan existed at ,a

certain depth, below the surface; and by means of the pore spaces this subsoil water is enabled to rise through the soil In t-his way the subsoil yielcfs water to the surface layers, an extremely important fact, at a time when no surface moisture in the form of Tain is available.

Soil and Subsoil. —Gardeners have for ages agreed that deep cultivation is essential for the best return in plant growth, and nowadays few will be found who do not believe that as the subsoil if often sour, lacking ;n the readily available elements of plant food materials and, therefore, less fertile than the suTface layer, tie should not be brought to the surface in trenching operations. - It is judged a safer method-to cultivate the subsoil, i.e., to apply humus yielding matter in "tho shape of vegetable refuse, animal manure, etc., to a subsoil which is merely loosened and not brought to the surface, at least until the decay of this vegetable matter has to a large extenc lost tho characteristics of subsoil. Humus in the soil is decayed vegetable matter, such as leaves, twigs, etc.; as a rule the black appearance of -soil :.- oie to there being plenty of humus :u it, and a soil containing humus holds water in suspension better than a soil devoid of «humus. In the early treatment of soil for a garden, one of the aims of the garden is to get good "body" into the soil. This is an indefinable quality, whose presence is not obvious in the mechanical texture of the soil and is intimately connected, with tho presence of humus or decayed vegetable matter, "Body" is easily obtained in most soils by the application of vegetable refuse in the lower stratum and of animal manure to what may be called the middle stratum of the soil. But animal manure is of so variable a quality that a word of advice to the gardener is. hero needed. He should not order the necessary manure without specifying the kind he requires and kriowing the epnditions under which, it has been stored previous to cartage. Horse manure is what the gardener terms "'hot" manure, that is, it is subject to more -rapid action of bacterial changes, acts quicker, becomes exhausted sooner, and rises to' a higher temperature than is the ease with cow manure. For autumn cultivation, therefore, since a quick acting manure is unnecessary, as the period of growth is still six months off, cow manirre is more suitable, though many gardeners prefer a mixture. Also for autumn cultivation fresh mjanure may safely be used on most soils, manure t-lrat has been partially covered and not lost much liquid is the best and proper thing. Some gardeners might take exception to the burying of manure to the depth of two feet ot so, that is, down to the subsoil; but there is ample reason for so doing, especially in the operation of trenching the soil. If the manure be placed in t-he upper reaches of the soil, plant roots finding material close at hand will natUTally fail to explore the lower regions of the soil for nourishment, and so the contents of the lower strata are left unused. But when the manure is buried deeply, a very much larger field comes under the action of the roots, wit-h the result that the full resources of the soil may be taken advantage of. Besides, animal manure has the f3eulty of absorbing a very great deal of moisI vturo supplied in the form of rain and yielding it up very strongly by percolation. Now, if the manure is close to the surface of the soil, this absorbed moisture will,-in all probability, be subjected to evaporation by the leat of , the sun's rays, especially in the ease *of light soils, and passing upward through the pore space, be quite lost to the growing plant. The only soil in which tho upper reaches should have, manure is clay, for in this ease the . decay of the manure leaves it more open, a result desired above all others by the gardener of such land. Leaving the Surface Soil Bough. In most districts it is desirable to permit the soil to absorb as much of the winter rainfall as possible, especially if most of the rain falls during that season. By breaking up the land and leaving it rough in early winter, the garden worker cau3es the earth to present many openings by which rain water may sink into the soil, while tie gTOund hinders the flowing away of water by its irregularities, besides a loose soil affords more pore space than does a close one, and therefore has greater power of absorption, that is, holds more water in suspension as the rain, percolates downwards. But this result is important in the direction of husbanding of moisture. The water in ■the soil freezes, expands, atfd in _the

act forces apart the particles of earth, thus making preparation for the free breaking up of lumps of eaTth; further, as by leaving the surface soil rough, a much greater area comes in contact "with the atmosphere, and is subjected to "weathering," a larger proportion of the plant food material comes under t«he same influence than is the case when the surface soil is smooth and level. Drainage. That moistuTe is absolutely essential for plant growth, is a recognised fact. Suppose we take some garden soil, spread it out to the air until *t becomes air dry, place it in. a pot which receives absolutely no water, and sow mustard seed in it, despite the fact that certain conditions favourable to plant growth are present —fertile soil, good seed, and correct temperature — yet, for want, of moisture, absolutely no growth takes place. A heavy clay soil may contain much moisture, while a light, sandy soil has but little, yet plants may grow well in tho latter and may die in. the former. The cause is not far to seek. Plant "roots lacking oxygen cannot grow, and if a soil is water-logged, air cannot penetrate deeply thrpugh the pore space. The result is that the roots must feed in the surface layer of the soil, w&ose store of moisture exists deeper down, ,it is valueless to the plants, as the roots cannot live in the airless deeper levels. But draining of this soil means the carrying away of water from tho lower levels, say three feet down, with the result that by. the force of gravity, the water in the upper reaches of the soil percolates downwards; air follows the water, and roots follow the air, until plants have a depth of two or three feet, in place of a few inches, in which to search for water and incidentally for food materials. It is. a fact that most of the rain falls at a period when there is very little growth, and a large part of it flows away over the soil,, drains away, or is evaporated. So that the main purpose of many of the operations of the gardener is the conservation of this moisture, anl of these operations dTainage takes the first place in the cultivation of the soil. Drainage is looked upon as merely a means of getting rid of superfluous moisture, thereby raising tho temperature and making clay soil earlier in Spring and for obtaining good results; but w-hat has been said will show thav

it also results in a great field being opened up to. the plant for its searcji; ofmoisture and food" material, by means? of its roots. Drainage as a rule is unnecessary in the case of light soils, t th:\t is, of sands or sandy loams withy' porous subsoils. Water percolates free-f ly downwards to the water table, to where all the pore space between the minute particles of soil is filled with water, and there is thus no fear of waterlogging. In the case of \eavy clay soil, where the particles, are much smaller than in sandy soils, the surface layer, instead of parting with the moisture downwards, becomes water-logged at the surface, and the water may take months to reach the water table. The purpose ox the gardener then is to create what may be called an artificial water table- by means of drains, and in this way to shorten the distance through which the water must percolate, and so hasten the . operation. Pipes shgukl lie laid at a depth *" of three feet A greater depth from the surface does not shorten the Jistanee. of percolation sufficiently; a smaller depth interferes with cultivation. As moisture is evaporated from the surface layers of 'the soil, the water from below ascends by capillary attraction through the pore spates and is in turn evaporated. This may proceed untiJ., the particles of the soil are robbed practically of all their moisture, which

in tJhtis way benefits the plants to no extent whatever. An examination of the soil in summer, which has been mulched with manure, etc., will show that ground which has been mulc&ed contains moTe moisture at a depth of 4 to 8 inches than that which is left uncovered,- and what is of consequence is that this is the region w&ere a large number of the young roots of herbaceous plants, etc, are found. The moisture held by manure, et<s> and the surface inch or so of loose soil, has certainly been lost by evaporation, but between the manure and the soil exists j air spaces so laTge that capillary water -cannot pass across them. Thus tvaporati'on ceases, and the soil underneath retains the moisture it holds. This implies that by mulching the soil, tho gardenerSr are able to a large extent to conserve the moisture which the soil contains. It will also be found frhat the temperature of mulched soil at a depth of six inches or so is lower luring summer months than that of uncovered soil at the same depth. This is easily explained by the fact that mulched contains more moisture than unnvjle>he-$ -, soils. Water requires more heat to raise it by one degree of temperature than earth does. So that by mulching the 'ground, with manure or soil the gardener provides for his plants a moister and cooler soil than if he does not much, (i.e.), just the conditions requir-' ed by plants in »hot, dry weather. Where the soil is mulched it must not be left too long without loosening the surface of the beds or border, a good inch, either with a Dutch hoe or fork, hut oa no account must the earth be stirred deeply in summer immediately around the plants or else the fibrous roots will be cut and t>he plants get a severe

check,