Dahlia (Cultivation Of The). Dahlias do not require too rich a soil - except those intended for exhibition, or show flowers, the management of which we shall treat of presently - in very nutritious ground they exhaust their vigour in producing strong stems and leaves, thereby causing the flowers to be poor, ill-formed, and few in number. A very barren, light soil, is equally unsuitable, and should be strengthened by a judicious addition of leaf-mould, before the plants are placed in it Where the soil is wet, heavy, clay land - the most unsuitable of all - it must be rendered friable by an admixture of drift or river sand, or, what is still better, road-scrapings. About November, the sand or scrapings should be laid over the soil to the depth of two inches, and well dug in, the ground being left rough through the winter; in spring two more inches should be laid over, and dug in as before. A moderately rich, light loam, is indisputably the best soil; but it must be borne in mind that this plant exhausts the ground to a remarkable degree, and consequently will not succeed, if grown too frequently on the same spot. A clear, open situation, freely exposed to the sun, without either shade or shelter, is indispensable for the production of fine blossoms. Those who have but limited space and few plants should place them singly, or otherwise, in the situations most advantageous for cultivation and display which their ground affords. No general directions can apply to particular localities. But where there is plenty of room, and a large collection of plants, no mode of growing the dahlia has such an imposing effect as when planted in a mass by themselves, unmixed with any other flower. When planting in a mass, two important objects must be kept in view, or else the effect will be spoiled. The first is to place the plants according to their respective heights; the second is, to associate them so that their colours may harmonise agreeably. If the clump is to be on a border backed by a wall or hedge, so that it can be seen only from one side, the tallest-growing plants must be placed in the rear; the next tallest in front of those; and so down to the shortest, which must hold the front rank of all. Bat if the clamp is to be formed on a bed which can be viewed from all sides, the tallest must be placed in the centre, :and the next in height successively downwards, till the shortest are placed in the front. To harmonise the colours - purples and crimson ., and Crimsons and scarlets, should be separated by yellow, white, or buff; the salmon-coloured and buff separated by white. The plants should be placed three feet from each other every way ; this spare will keep each plant sufficiently distinct when close to them, and yet so united that at a short distance the whole clump will appear as a solid mass; it will also afford room to get amongst and attend to the plants. Another mode of planting: dahlias, which exhibits a grand effect, is to place a row on each side of a walk as an avenue; in such position the plants need not be more than two and a half feet apart.
Dahlias are propagated by dividing the tubers when they have formed incipient shoots, by seed, and by cuttings. As the last method is comparatively useless to the amateur, we shall not take up space to describe it, but, proceed to the first two. The roots - or more properly speaking, the tubers - should be kept cool, inactive, and entire, until the beginning of May, when they should be planted out in the open border, barely buried in the soil, and covered with a hand-glass. The eyes of the tubers will soon push forth young shoots, and when these have attained the length of two or three inches, the tuber should be cut with a knife, so as to retain a portion of the tuber attached to each shoot. These young plants may be placed in pots with light soil, and kept in the house for a short time; or they may at once be planted in the borders where they are to flower, sheltering them from the sun by day, and from cold at night, until they are established. Another method, slightly different indeed, is to place the roots in a warm situation - in a south bonier for instance - covering them all but their eyes with rotten bark, leaf-mould, or other light material; when the buds break, divide as before described. It is a 6afe plan when dividing the roots, to cut so as to secure, if possible, more than one promising bud on each piece. It is satisfactory to know, that excepr in florists' gardens and large establishments, where quantities of plants are required early in the season, artificial heat is not required for propagating the dahlia from the tuber. We have the high authority of Mr.
PaxtOn for saying, that plants raised according to these methods, frequently grow stronger and flower better than those
Which have been raised earlier in the son by the application of beat.
When the young plants, by whatever mode obtained,are finally planted out where they are intended to flower, the apper part of the root should not be less than three Inches beneath the surface,and the soil should carerully sett led down about the roots by gently pouring in water as the hole is being rilled up. A large sized flower-pot inverted over the young plant makes an excellent protection at night; and shade may be afforded in the day-time by branches of fir or laurel stuck in the ground. A stake suitable to the full height of the flower must be inserted and fixed firmly into the ground close to the stem, at the time of planting. This is imperatively necessary; for the insertion of the stake after planting is sore to injure the roots, check the growth of the plant, and destroy its beauty. The leading shoot, as it advances, must be tied to the stake with strips of bass. These bands must not in the first instance be tied too tight, and frequent attention must be given to sec that they do not hinder the stem from swelling to its full size. During the whole period of growth, the soil about the roots should be kept moderately moist, but not over-drenched, with water, which to this plant is equally as injurious as drought. If the soil be light, and the summer excessively dry and hot, a layer of fresh cow manure for about two feet round the base of the stem of the plant, is highly recommended as a preventative to too rapid evaporation.
Having described the culture of the dahlia, from the tuber to the flower, we shall now turn to its most interesting mode of propagation. It is from the seed alone that all new varieties are obtained, and it is only from the seed that the plant has been, and, no doubt will be, so greatly improved. About the middle or end of January, the seeds should be sown in shallow pans placed in a hotbed frame, near the glass, and. exposed to the light; as soon as the seed-leaves are properly developed, the young plants should be pricked out into other pans, at the distance of an inch from each other; they should then be watered, and shaded for a few days until they recover the shock of this, their first removal, and are briskly thriving again. When they have attained the height of two inches, they should be potted, singly, into small pots, and gradually inured to a lower temperature. As they increase in size, they require to be shifted into larger pots; and advantage taken of all opportunities of hardening them for the open air. The seedlings may be planted out, in the open air. about the end of May, and the course of culture already detailed must be followed. Until the seedlings show their flowers, there are no means of ascertaining, with certainty, their quality or colour; though it has been observed that plants with wholly green stems produce white flowers, those with brownish stems the darker coloured flowers, and those with light-coloured stems pale or blush-coloured flowers. When the blooming season arrives, the seedlings should be examined early each morning before the sun has shone upon the flowers, as their true colours are better ascertained at that time of day. Such plants as are considered unworthy of preservation should be at once pulled up and thrown away, for they will only exhaust the soil to no purpose; and those which having proved good are worthy to be retained, should not be Buffered to bloom profusely, in order that the tubers may retain more nutritive matter, and thereby be better able to produce strong and healthy plants in the following season. The tubers must never be subjected to the destructive influence of frost. About the end of September, some ashes, saw-dust, peas-haulm, or other protective materials, should be laid over the roots; and when the stems and leaves turn black, the plant should be cut down to within six inches of the ground. A few days afterwards, taking advantage of a fine morning, the tubers must be lined, and laid exposed to the sun during the remainder of the day. When the soil about the roots is dry, all that can be removed without injury should be taken off. The tubers may then be buried in dry sand, or laid on a shelf or boarded floor where they will be perfectly free from frost and damp, and in a moderately cool temperature, being at no time, through the winter, higher than forty-five, nor lower than thirty-six degrees.