When one sees the things done in the great botanic gardens and by large nurserymen in the way of shifting trees, one wonders whether there is any limit to the powers of arboreal experts. They almost remind us of the strange deeds of American house-shifters, who transfer whole dwellings en bloc from one site to another. Little is thought of shifting a tree twenty feet high, with a bole nearly a foot through. It is merely a question of labour and tackle. A considerable block of earth is taken with the tree, and very few roots are left behind. Every gardener likes to shift with what he calls "a good ball." The ball is the mass of roots with adhering earth. Well, the ball in the case of some tree-lifting which goes on is a mass weighing, with the tree, several tons.
The great compensation for the labour involved in isolating and hoisting such a mass is that practically all the roots are secured and the tree hardly feels the shift. The labour is really considerable. A trench is cut all round when the area of the ball has been marked out. An approach is made to the cube on one side. This approach is a slope dipping from the ground level to the base of the cube. Stout planks are worked beneath.
The ball is thus isolated. Canvas is wrapped round the mass, ropes attached, and the hoisting and swinging tackle hooked on. Provision is made for maintaining the equilibrium of the tree with guy ropes. When all this has been done it is merely a question of power for getting the mass out of the ground.
Operations of this kind have the interest that attaches to all big things, but they are not likely to come within the practical experience of most garden-lovers. Such shifting of shrubs and trees as is done in ordinary gardens is limited to moving things that are within the powers of two or three men. The main object of the present chapter is to urge that courage should be exercised when a serious mistake in shrub or tree planting has been made, and that before the owner makes up his mind that it must be permanent he should carefully, but at the same time boldly, consider the situation. Resignation in the perpetuation of an error should be the last resource of a true garden-lover.
There may be cases in which an amateur wishes to make changes when the shrubs or trees have become large. He has several things to consider. To begin with, can he expect the plants to move safely? If there is the least doubt he will be prudent to consult an expert. Assuming that an encouraging reply is received, the further question arises, will it be true economy to shift, in view of the fact that a special machine or tackle, and the services of several men will be necessary? It may help to solve this problem if the expert is prepared to give an estimate for the work. A nurseryman who is used to shifting large shrubs and trees can calculate the time that a particular job would take, the number of men, the character of the appliances, and the quantity of horse labour that would be needed. Thus situated, he is able to say what the whole undertaking would cost.
A reasonable limit for the powers of an ordinary garden staff might be set at trees eight feet high with boles four inches thick, and shrubs fifteen feet in circumference. The writer has not hesitated to operate on subjects of these dimensions with three assistants, with the ordinary tools of a garden and with a sheet of strong canvas. First a trench has been cut a yard from the stem all round the plant and a foot deep. This enables an idea of the root stock to be formed. If it is compact and fibrous the problem becomes one of straightforward labour alone. If there are a great many thick, spreading roots matters are complicated. Nearly all evergreens have a fine fibrous root system, but most deciduous trees have a coarse spreading root system. Those who have the shifting of a large deciduous tree in view might cut round it a few months beforehand and ram in some good loamy soil, in order to encourage the formation of fresh fibrous roots. With these to support the tree there need be no hesitation in cutting through the stronger roots two or three feet from the stem, as the tree can do without them. If shifting has to be done at short notice, so that the tree cannot be fortified by preliminary preparation, the operator must do the best he can. He must not expect to secure all of the existing roots if the tree has been standing a few years, for they will have spread in various directions and some may be fairly deep; but he should try to preserve all the shorter roots near the bole, particularly the fibrous ones, and two feet or more of the others.
It will be wise to prune back the branches before replanting.
The great majority of evergreens "move" quite readily, as stated in Chapter 7. There is scarcely a period of the year when they will not endure removal, provided air and soil are moist, but one would hardly be disposed to try experiments when they were in full bloom. There is no better time to shift Rhododendrons, for example, than mid-spring, although the flower-buds are plump. That would not be the best time to remove deciduous spring-flowering shrubs, because they would be filling with young leaf; but this class can be removed with complete success in a wet spell after midsummer when the new growth for the year is complete, yet the leaves still on. One great advantage of moving in advance of leaf-fall is that a correct idea can be formed of what the shrub really is. There is a vast difference in the summer and winter aspect of, say, a Weigela. In winter the shrub is a mere framework of ribs, and does not occupy nearly so much space as when furnished with full flesh and blood. No doubt a good many mistakes are made in planting deciduous shrubs because this difference is not taken into sufficient account.
The three vital things in the success of summer shrub-lifting are:
(1) moisture both of soil and atmosphere;
(2) securing a good ball;
(3) working quickly.
Fig. Staking standard trees. The heavy bars show the outline of the hole. The vertical dotted line represents the stake put in with the tree, and driven down into the subsoil to insure a firm hold. The stem of the tree is protected at the ligature A.
Fig. Depth of planting trees. If planted up to A it would be too deep, if at C too shallow. B shows the right point of covering, that is, just above the top roots.
Without moisture it would be difficult to get a good ball, except when operating on a very retentive soil; there would be a considerable, and perhaps disastrous, crumbling away. Given moisture, the mass of roots and adhering soil is quite homogeneous. Sure of his position, the operator may even trim the edges of the ball so as to get rid of superfluous soil, but he must do this with circumspection. The ball should not be left exposed, but wrapped in the canvas, carried away and replanted at once.
My own plan is first to make the hole of the size which I judge the ball will require, then to carry a mat or cloth to the shrub and directly it is lifted to wrap it in the cloth and carry it away for planting. At the planting site ball and hole are made to fit each other, mainly by application to the hole, possibly, however, in part by trimming the ball.
How can we get the desired "ball"? First by operating in or after a spell of wet weather; next, by working round the shrub in a circle with the spade to a depth of a foot or so and half a yard or thereabouts from its centre, more or less according to its size, and then undermining it. The shrub will come away the more readily if one workman pulls steadily at a point opposite to the spadesman. It is well to have a chopper at hand in case any strong roots are found. The shrub will not be injured if these are severed a foot or more away from the tree. Such roots are more likely to be found on deciduous than on evergreen shrubs, most of which produce thick masses of fine fibrous roots.
Fig. Lifting Evergreen Shrubs. The dotted lines show how a large "ball" maybe trimmed with a sharp spade, leaving an even smooth mass of roots and soil.
Fig. Lifting Shrubs. Shows how a trench is cut all round the shrub with a spade at the outset.
If the wet spell which encouraged the undertaking should change suddenly to a dry one, it would be wise to syringe the plants for a few days.
The general moving of shrubs and trees is done between November and March inclusive. But winter moving is not the best in retentive ground, because the soil is apt to be sticky and when trodden in (and firm soil is an advantage) binds into a close mass almost impervious to air. In such soil the grower should transplant as early in autumn as possible, or in spring, if circumstances are not favourable, or if courage is insufficient for the heroic measure of summer shifting.
Let him beware at all seasons and in all soils, but especially in winter on retentive soils, of "puddling in" shrubs and trees by turning the soil into a paste. It is not merely unnecessary, it is highly dangerous. But firm planting is good; so long as the soil is friable and crumbly there is little fear of its being made too hard.
The following is a summary of the periods of planting the principal kinds: -
Evergreens generally. - Late summer in showery weather, or mid-April.
Rhododendrons. - Mid-April to mid-May.
Bamboos. - May.
Laurels and Hollies. - September or April.
Deciduous shrubs and trees generally. - Late summer in showery weather, failing that, any time up to the end of March, but preferably November.
Magnolias. - Early autumn or mid-spring.