This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
Prof. Undley.-In The Gardeners' Chronicle
There are no doubt places in which all the skill of the planter will at first fail in getting trees to grow, but even in such cases he need not despair; the cause of his failure usually is, not that the soil is absolutely unfit to support vegetation of any kind, but that the circumstances being highly unfavorable, the plants are not able to get over that shock to their systems which they always suffer in ordinary transplanting. It is evident that plants which are moved with bare roots, as young trees are, must receive a far greater check than those which are moved with a ball of earth; and it is very often found that a little extra care in the planting is well repaid, because if the tree survive this check, and form fresh roots, it will generally get such a hold upon the soil, that it is then able to* grow up, and form a healthy tree. In planting the most barren and exposed situations then, particular care must be taken, and it appears in such cases to be well worth while to add some "improver" to the soil, thrown into the holes in which the trees are planted.
The quantity required is small, it's cost need not be great, and the labor of using it is a trifle, compared with the good effect produced by its application.
The effect which it is desired to produce is the formation of fresh roots, and any substance which will cause the plant to throw out a quantity of fibrous rootlets, will enable it to overcome the evil effects of its being transplanted. It appears that phosphoric acid possesses a very great and remarkable influence on the development of roots, causing plants to throw them out with unusual vigor; we do not know of any very satisfactory explanation of this phenomenon, either chemical or physiological, but of the fact itself there seems to be no doubt. The most convenient mode of employing this substance is in the aids greatly in the formation of root fibres, and consequently assists very much in establishing the plant in its new situation. Or, if scattered over the soil next the roots, before it is finally watered after planting, it is well distributed to the places where it is most required.
When a young tree has its roots thrust into such a hole as is made by a single cut of a spade, or even by two cross cuts, the roots are crowded together, and crushed into a small space; they are unfitted therefore to collect and absorb nourishment, at a time when the plant stands peculiarly in need of it. Not only is the freshly-planted tree able to obtain little food by means of its roots, in consequence of the mode in which it is planted, but the supply of nourishment is at the same time also diminished inconsequence of the change of soil. In all cases the soil of the nursery or seed plantations, having been repeatedly dug over, and more or less manured, is better suited to the growth of the young plants than the soil into which they are transplanted can possibly be. When a plant is moved from one soil to another its growth is always checked, and the first step which it makes towards repairing the evil thus caused, is the formation of fresh roots; by bad planting this is made as difficult, as possible to the plant.
It is hardly fair to compare together the growth of trees with that of the ordinary vegetables which are cultivated in our kitchen gardens; of course the conditions necessary to the growth of an annual, differ from those proper to the healthy development of a slow growing tree, which requires a long series of years to arrive at maturity; but even in the case of common garden crops, the same general effects to which we have just referred, may be observed. In almost every case where it is desirable to increase the development of roots, phosphoric acid is of the greatest value. When we wish to force young plants, to push them forward as fast as possible, so that their roots may get some hold upon the soil, the superphosphate of lime is one of the best manures we can employ. The mode in which that substance brings forward a crop of turneps is an illustration of this, and the remarkable way in which it assists the growth of the young plants, getting them rapidly into the rough leaf, and producing a more marked influence on their growth then, than it does at any subsequent period, appears to depend chiefly on the fact that it aids them in the formation and development of roots.
Superphosphate of lime is, therefore, a very valuable fertiliser in the hands of the planter, but in using it he must always remember, that as his plants must necessarily absorb the whole or the greater part of the soluble manure which he gives them, he must take care not to give too much, He must not suppose that if one handful will do good, therefore ten handfuls will do more: it is very easy to give too much, and plants, like animals, may equally be injured by over feeding or by starvation.