Standard fruit trees should never be planted in a kitchen-garden, as from their drip and shade it is impossible to grow good culinary vegetables under them; while, on the other hand, the constant digging and movement of the soil required for culinary vegetables, make the roots of the trees descend so far that they get beyond the reach of the air, and can never produce good fruit. Dwarf standards are fruit trees grafted near the collar of the plants, and trained in various ways to form bushes rather than trees. Sometimes a hoop is placed inside, and the branches are trained into a cup-shape; at others, the branches are formed into a kind of umbrella; and, at others, they are trained into the shape of a distaff (en quenouille), or like a pyramid. All these and many other modes of training dwarf standards may be seen at the London Horticultural Society's Garden at Chiswick: but only pears, apples, and dwarf cherries are treated in this manner; and, though they are convenient to gather the fruit from, they are in so unnatural a state as to be subject to canker and other diseases, and seldom live long. Espalier trees are subject to the same objections, as they are in a still more unnatural state than dwarf standards. The hardy kernel and stone fruits are therefore best grown in an orchard, and I shall now say a few words on their treatment.
Apples are the most useful of all fruits, and there are three distinct kinds, the dessert or eating apples, the kitchen or baking apples which fall or become soft in cooking, and the cider apples which are good for nothing but cider. Apple trees are generally grafted on crab stocks; and, when they are planted, the collar should be raised a little above the soil, as if it is buried the tree will very probably become cankered, or affected with the American blight. Canker is sometimes cured by cutting out the cankered part, and admitting air to the roots; and the insect called the American blight may be removed by washing the tree with a brush and soft soap and warm water, or by plastering it over with a mixture of stiff clay and water.
Pear trees are very apt to send their roots down to a great depth, and then cease bearing; so that it is desirable to keep the roots near the surface by mulching with manure or dead leaves. The fruit is produced on spurs, and when pear trees are grown against a wall they are trained horizontally, with short projecting branches or spurs. Pear trees against a wall are very apt to bear their fruit in clusters, and to leave a great part of the tree barren; and this arises from their flowers having naturally very little pollen, and, where the flowers are exposed to great heat, the pollen drying up without fertilising the stigma. The best remedy is to syringe the branches occasionally, and to shade them when in blossom.
The quince thrives best near water; as does the medlar. Mulberry trees are best planted on a lawn, for the convenience of picking up the fruit clean from the grass; as it falls as soon as it is ripe. Plums and cherries require no particular care when grown as standards, except to be sparing in the use of the knife, as both trees, when wounded, are very apt to produce gum; and this, which is an unnatural exudation of the sap, similar to the bleeding of the vines, is very injurious to the trees.
The almond is a kind of peach tree, with a leathery fruit instead of a juicy one, the almond being the kernel of the stone. The bitter almond abounds in Prussic acid; but this powerful poison scarcely exists in the kernel of the sweet variety. Almond trees are generally grafted on plum stocks; and they should be grown in a dry soil and a sheltered situation, as the branches are brittle and apt to be broken off by high winds. When almond seeds are sown, the sharp end should be pressed downwards; and the young plants should not be transplanted except when absolutely necessary, as they have very long tap-roots. When the almond is planted for ornament it should have a back-ground of evergreens, as its flowers appear before its leaves.
The walnut, being a spreading tree with large leaves, should only be planted where no injury will be sustained by a deep shade being cast upon the ground; but it must be observed that its leaves are disliked by all cattle, and are injurious to cows. In pruning it the tips of the branches should be taken off, to make them throw out fruit-bearing shoots.
Sweet chestnuts are always propagated by seeds, and never grow well unless the soil contains a portion of sand. The wood is worthless when old. Both walnuts and chestnuts are generally planted in the park.
The fruit shrubs grown in gardens may be considered to include the elder, the berberry, and the filbert, though these are frequently called trees. The elder and the berberry will grow anywhere, and require no particular care in their culture; the filbert is only a variety of the common hazel, and both are generally grown on the borders of walks, where they are planted from five to ten feet apart, according as they are to be trained upright or spreading. As the fruit is produced on the young shoots, the bush should be kept open and trained in the cup fashion, in order that the main branches may throw out short young wood. Filberts are propagated by sowing the seeds; and hazel trees by suckers, which they throw up in abundance.
Gooseberries are generally propagated by cuttings, which strike easily; and they should be grown in soil which is well drained, and well manured by a coating of rotten dung being laid upon it every third year. The bushes should be planted in rows eight or ten feet apart, the plants being about six feet from each other. They should be pruned twice a year; in the winter to remove the branches not likely to produce fruit, and early in summer to remove those shoots that are not likely to ripen. The fruit is produced partly on the old and partly on the young wood, and it should be thinned when gathered green for pies and puddings, by taking only a few from each bush, instead of gathering all that may be wanted from one.
Currants are raised from cuttings generally about a foot long, all the buds from which are taken off, except five or six at the top; and the cutting is then firmly fixed in the soil about six inches deep. The currant bears chiefly on spurs of the old wood, so that these only are generally left in the winter pruning. The currant is very hardy, and will grow in any soil or situation, even under the drip of trees.