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.
Apricots in pots are very rarely seen, even in large establishments; they are difficult to force, as they will not bear the confined air of a forcing house. I remember, some years since, being much struck with some apricots cultivated as dwarf trees in the South of France: the trees, full of their golden fruit, looked so beautiful, - at the time I wished that our climate would allow us to grow them in the same way. I did not then think of cheap glass, root-pruning, and pot culture.
It must always be borne in mind that, without abundance of air and the full light of an unshaded roof, - by this I mean that no vines must be trained under the glass, - fruit of high flavor cannot be grown; the trees will bear well, but their fruit will be vapid and flavorless.
The best trees for pot culture are those that have been in pots one or two years: if these can be purchased, so much the better. The next best are trees that have been removed and cut down one year in the nursery. If neither of the above can be found, "dwarf maiden trees "* will do. Trees taken from the open ground must not be potted till the end of October. Presuming that potted trees have been procured, they may, early in October, - if omitted then, in November or December, - be repotted into pots of the size selected for this system. I have named 11-inch pots, because they are portable, and the trees may then be shifted into large pots as they advance in growth; 11-inch pots will, at any rate, do well to commence with. October, November, and December, are the best months for potting trees; they may indeed be potted till March, but then no fruit must be expected the first season. If fruit-bearing trees that have been grown in pots can be procured, they cannot be potted too early in October.
I know of no compost better for stone-fruits than two-thirds turfy loam and one-third decomposed manure, to which some road or pit sand may be added. The loam should not be sifted; if it contains a large proportion of lumps as big as an egg, so much the better. If you examine an 11-inch pot, you will find it eight inches across at the bottom, and the aperture from one inch to one and a half in diameter. Take a light hammer, and enlarge this aperture to five inches in diameter*; then place four or five large pieces of broken pots or tiles across, so that they rest on the inside ledge left by the hammer, leaving interstices for the free emission of roots: on these place some of the most lumpy part of your compost; then your tree, not too deeply, but so that the upper part of its roots is a little below the rim of the pot: if it has a ball of earth, loosen it; fill up with compost; ram the earth down firmly, as you fill, with a stout blunt-pointed stick; place it on the border where it is to grow during the summer; give it two or three gallons of water, and a top-dressing of some manure to lie loosely on the surface, and the operation is finished.
We will suppose that our tree, a nice dwarf bush, with five, six, or seven branches,† is potted. It may rest till February, and then be pruned, - a pleasant, simple operation, more easy to show than to tell how to perform. I may as well now state that the pruning recommended here for apricots will serve for all bush fruit trees under orchard house culture, except peaches, nectarines, and figs. Each branch must be shortened with a sharp knife to ten inches: these shortened branches will form the foundation of a nice regularly-shaped bush. In May each branch will put forth three or four shoots: all of these but the topmost one must be pinched off to within about two inches of their bases: they will form fruit-bearin.g spurs; these will continue all through the summer to make fresh shoots,:which must always be pinched off to a length of two inches. By the end of the first season the leading shoots of the tree will be probably three feet in length, and, as well as the spurs, be furnished with blossom-buds. The summer is past; the month of October is with us.
Its shoots are ripe, and the tree has ceased to grow: it must be put to rest for the winter, by lifting up the pot and cutting off closely every root that has made its way into the border: it is then ready for its top-dressing, the method of giving which I have described further on.
The second season: - in February, or early in March, the leading shoot made the preceding year, and which ought to be from two to three feet long, must be shortened to ten inches, and the young shoots as they push forth in summer (all but the leader) be pinched off as in the first season. The third season: - as the tree will have increased in size, its leading shoots may be shortened to six inches, and as it becomes aged and" fruitful, annually to four inches, and at last pinched off in summer to two inches, as to make a compact round bush. In the course of time some of the shoots in the centre of the tree will require thinning out with the knife, if at all crowded.
The general management of the trees the second year should be as follows: -
February is with us, and, if the season be mild, buds are beginning to swell, and flowers to bloom: the trees in your orchard house are, however, dry, dusty, and stagnant; place them in their stations, three feet stem from stem, give each of them a small quantity, say a pint, of water, - not, however, if the winter is still raging, - let them rest three days, then give them a quart each - in short, gradually saturate the earth in the pots, and afterwards water them regularly according to the state of the weather. The buds, if the weather is mild, will soon begin to swell, and in March, or early in April if the season be late, they will put forth their full bloom; and beautiful things they are, for no frost, no storms, will destroy the blossoms. If the weather be sunny, with sharp frosts at night, as is often the case in early spring, the shutters, both back and front, may be open all day and closed at night; if a wind-frost and cloudy weather, they may be closed day and night; the ventilation through the joints of the boards will then be amply sufficient. With this treatment nearly every blossom will set.